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 Computer Monitor Repair

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مُساهمةموضوع: Computer Monitor Repair    الخميس مايو 26, 2011 4:04 am


Computer Monitor Repair






QUESTION NO.
P101702-6: IBM 6547-0BN monitor has a faulty HOT SEC5088. Could
not find any other faulty components, but when I replaced it, the transistor
promptly blew again, what other components could be responsible?

What replacement
did you use for your SEC5088? Proper number for replacement is
KSC5088. 2SC5088 is not equivalent.










QUESTION NO.
P111802-2: AOC 5E monitor FCC ARSCM350S. Need part number of
D922.

This is a high
failure part. Original is STPR320. It should be replaced by SUF5402 or
UF302G.




QUESTION NO.
P110602-1: Sony CPD200GST monitor Scc-L70b. Q513 s/c. After
removing ( or replacing ) Q512,515 & 516 get hot with line fold over on
the screen. R578 looks stressed and reads 20k. Voltages seem OK on these
fets.

R578 is 27 ohms, 1
Watt, flameproof, in the schematic, so replace R578. Also check C573
(4.7 uF/250V) and L506 (0.47 mH), in series with R578. If this does not
clear up the problem, I would check transformer T503, C504, C505, and then
flyback T501.

Have the same
monitor. Different SMPS fault though. R578 is a 27ohm resistor ,
not 20K.




QUESTION NO.
P110802-8: Daytek DT-14ST39 monitor, vertical deflection IC301 burned
completely, only ST (SGS-Thompson) logo visible. Multiwatt 15 package
IC code number needed to get replacement (TDAxxxx).

The vertical IC is
TDA1675A; Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists it.

IF the TDA is
visible then the rest is likely TDA9302H or TDA8172 or TDA8176 in which case
you can sub 8172 for 9302 but not the other way around. The IC is 7 pins 4
bent behind & 3 in front and (15 pin in the same configuration is
TDA8176).. I don't have schematics, but have changed a few of these. There
are a few single in line versions which have more pins.




QUESTION NO.
P110802-4: Acana Advance 17S monitor FCC IIBUAI has no vertical
position adjust.

Check transistors
Q302 (NPN) and Q303 (PNP).




QUESTION NO.
P110402-6: Sony GDM-20se1 monitor FCC ak8gdm20e01. Replaced Q511
and IC404, unit came back after 3 months. Replaced Q511 and PS001 (on
crt bd), lasted for 2 weeks then Q511 blown again.

Check the
electrolytic capacitors on the power supply board; C610, C611, C612, C614,
C615, etc, etc. When these caps are marginal or have high ESR, other
components become stressed. If Q511 shorted, also check Q512 (leaky?), D504,
L508, and fuse PS500.




QUESTION NO.
P110102-4: Acer 54el FCC JVP7154E monitor has no display.
Replaced HOT and cap C335. Switch ON and got display but after a few
minutes HOT burned again. Replaced flyback transformer but did not
help. Checked others component okay.

If C335 was bad, it
is possible that IC201 (TDA4858) was also damaged, and needs replacing; also
check the value on R214 (15K). Also check components in the base drive
circuit for the HOT, and check/replace C319, C320, and C326.




QUESTION NO.
P103102-7: Apple / LG M2978 BEJCA500 m/scan 15 replaced B+ fet & 3
caps on the line but need D708 ID not a number format I have seen before K1 -
4 - 56 need values.

Took a chance on
D708 with the only reference close to it was Sanken's RK14 40volt 1.7A
schottky. Used 1N5822 with rebore, D707 is also the same located
adjacent to D708.

I believe this is a
Sanken EK14, a 40 Volt, 1.5 Amp Schottky diode. You probably can substitute
an ECG/NTE 586 for that Schottky, if it is defective.




QUESTION NO.
P110502-9: HP ultra VGA 1024 monitor model D2825 FCC JVP7154E Hitachi
chassis blinks on and off after five minute warm up. When this happens
the select buttons do not work. The last mode LED selected will stay
on.

Replace the small
ceramic disk capacitor C335 (220 pF/2KV), located near the yoke
connector. Sometimes this is all that is needed. Use a good-quality
capacitor; a 3KV rating is best. Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is
one source. If R214 (15K) is suspect, replace R214 and check IC201 (TDA4858),
as well. Also check for bad solder in this area. This HP is an Acer
chassis, not a Hitachi chassis.




QUESTION NO.
P110402-2: Gateway CS1572FS monitor, video looks good, but picture
icons smear to the right leaving a light tail on the screen.

The CRT may have
gone bad; this is especially likely when a Toshiba CRT is installed. If
the CRT installed is a Hitachi, you might try changing all the 1 uF
electrolytic capacitors (both polarized and bipolars) on the CRT board, and
also checking C332.

Check the caps on
the crt board. Bad or low esr will cause this condition. If all
caps are good, try attaching a ferrite core around one or both ends of the
video cable if no so equipped.




QUESTION NO.
P110402-4: Mag 570v monitor with transistor or FET shorted, FS12KM5,
was wondering if there is a suitable cross for this. Have not been able to
locate a source for this part.

FS12KM-5 is a
Mitsubishi N-channel Mosfet, rated for 250 Volts, with Rds[on] < 0.4
ohm. FS12KMA-5A is a possible substitute; also, IRFI644G, which is
listed by Digikey ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
Hitachi's 2SK1762, listed by B&D Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and
Hitachi's 2SK2426.




QUESTION NO.
P103102-1: Compaq 623t monitor FCC br8sm-769a. Replaced faulty
fbt. Now have very narrow vert line from top to bottom. Checked
most components in horiz stage.

R866 and R534 both
2.2 ohms 1/4 Watt both carry about 192 Volts from power supply, R866 to fbt
and R 534 to yoke driver. The yoke driver's 192 volts is cut off with R
534 open, that is why you have a narrow vertical line. Also check C 860 and
C533 both are 33uF 250 volt caps, especially in this case where R534 is on
same circuit as C533.

The FBT is driven
by Q831, but Q803 drives the horizontal yoke. Q803 might be bad, or
lack B+ on its collector, or its base drive may be missing. The
horizontal yoke itself may also be open, or have bad solder connections.




QUESTION NO.
P103002-2: Medion 1772IE monitor. Need values of R329 and R356,
these have blown and are unreadable.

Believe your
monitor will revert to an Acer 7276E where R329 is 10K and R 356 is 47K if it
has an FCC ID of JVP7276E that will be it. The schematic is available on the
Russian and CZ sites or try FTP 24.197.70.237.




QUESTION NO.
P110102-8: Radius 0381 monitor, the original fault was no H scan due to
PS101 being O/C. Now it does not lock horizontally unless H-Freq pot
adjusted to one end and then only at 48kHz or above. The LED's on front
status are all lit except for Brightness led.

Answering the fault
myself for the LED's, it was in service mode, a switch inside.




QUESTION NO. P103102-3:
Viewsonic 21PS monitor with no heater voltage. I traced continuity back as
far as I can into the power supply area.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:05 am





This chassis has a
common problem, with C867 going bad, leaking fluid, and eating the PCB traces
under it, on the top-side of the board. Pull the C867, and if any
leakage or corrosion is seen, clean well; if the heater PCB trace underneath
C867 is damaged, jumper it. Also, C839 gets this fluid leakage, as well; so
it's a good idea to check it also.




QUESTION NO.
P102802-10: Dell ultrascan P1110 monitor with an excessive
brightness/raster with slight color purity problem. Fault seems to be
on small logic board situated on the base of the monitor and I am am unable
to pinpoint the fault. The board has a Sony ic, I changed the whole
board to cure the fault short term, but I am seeing more monitors like
this. There are no adjustments other than focus.

This Dell is like
the Sony G1-chassis types, and it sounds like it needs a Sony DAS (software)
alignment, which can adjust the G2 voltage (assuming yours is excessive), as
well as adjusting the white balance.




QUESTION NO.
P102102-3: Compaq 462 monitor has no brightness control. I
measure -28v on one side of the Brightness pot, and -10v on the other side.
G1 measures -150v, and not changing with the brightness pot.

If this is the model I recall the screen
being over bright with no adj, turned out to be 2.2 ohm resistor on the video
board. There are three all up half watt.




QUESTION NO.
P102902-4: Panasonic Panasync S110 monitor Chassis HV10S has no
display. B+ is normal, Yoke drive OK. No drive to flyback and no
output from IC671.

Review Question
number P60602-5. Also check J114 which on this model may be 800mA
microfuse or as the S110i has Q861 is the same thing on the 185V rail.
Check Q881, Q549 & R890 also review Question P311-4.

The flyback
transformer (TLFA01365) is very high failure in this chassis. Check out
the flyback's internal capacitors, from the HV anode to pin 14, and to pin
15. If the capacitor to pin 15, that gives HV feedback for IC671, goes
leaky/shorted, the output from IC671 can become reduced, to very narrow
spikes, or shut off. Also check if IC671 is now bad.




QUESTION NO.
P102802-9: Sony GDM-400PS monitor. Have reviewed Q P54-3 and
others, I suspect IC007 (CXA2043Q) but need confirmation of symptoms, picture
rolling vertically with pin moving in and out as scrolling, squashed slightly
at top but full screen and all adjustments appear to work, looks like stuck
in adjustment loop. The manual I have does not show the IC007 voltages, other
main components check OK. The no input message after signal down is OK and
self test steady picture, but OSD when signal applied goes haywire with the
rest, are we looking at IC007?

A defective IC007
can give a range of geometry-related symptoms, and yours are among
them. For instance, distorted/squashed display, scalloped sides,
jitter, unstable raster or scrolling, and the adjustments often still
function. However, since IC007 is pricey, and its PCB traces are delicate,
you might wish to first check C712 and R728, off IC702, in case one of those
components is bad.




QUESTION NO.
P100202-10: NEC MultuSync 95 monitor had initially dead HOT and fusible
resistor. After replacing them HV first reaches about 15 kV then
switches off. HV and H outputs from processor tda 9111 disappear. Looks
like X-ray protection, but Vcc for processor is only 10 volts (should be more
than 10.Cool. Replacing of processor doesn't help.

Check that the
value of R155 (0.22 ohm) is exact.




QUESTION NO.
P102102-5: Mitsubishi DiamondView 1554 monitor, when switched on, light
next to switch is blinking with ticking sound. C335 is blown, what
value is it?

My notes say C335
is 220 pF/2KV..




QUESTION NO.
P102102-6: Gateway monitor EV900-70000595 Model X19001 has no high
voltage. Power supply is ok but no b+ to collector of horizontal out
transistor Q112. Q112 is fine. There is 200v on drain of MOSFET Q107. There
is a hissing noise from power transformer.

First, if the power
LED is green, resolder all legs of L501. If no help, check D315 in the power
supply secondary, FET Q107, and the flyback transformer. If the FBT is bad,
check whether any resistors in the ABL circuitry have burned.




QUESTION NO.
P102102-7: AppleVision 850 monitor has no picture or CRT illumination
and no on-screen controls when adjusting front panel buttons. Monitor
reacts normally when connected to CPU including degauss and power switch LED
color change from orange to green.

Does the monitor
also have high voltage come up on the CRT? If the monitor lacks HV to
the CRT, there is probably a hardware fault. Try checking RL163 (4.7 ohm,
fusible), QL2, QL23, and check solder joints nearby these components and on
the horizontal yoke connector. If HV is present, after all, the internal
memory settings may be corrupted. These can be restored, using an ADB-type
Power Macintosh computer (ADB cable must be attached), if that Mac has in its
System folder, an °Applevision Extension of version 1.5.3 or later (roughly,
Mac OS 8.5 or so). Do a boot-up of the computer from power-off, with
both video & ADB cables attached to the monitor, while holding down these
four keys, Command(Apple)-Option(Alt)-A-V. Continue to press all four keys
for the few minutes it takes to complete the boot-up.




QUESTION NO.
P92402-9: Acer 7277C monitor with the Horizontal Size control and
Pincushion not working, all the other geometry controls are working
perfectly, and it has R334 burned, don’t know the value.

R334 is 22k
1/4W. That problem is related +B generator, replace the C323 (33U X
250V). Normally that is it.




QUESTION NO.
P101102-1: HP A4033A monitor the amber power save LED and the green
POWER LED blink and the GEOM LED is solid. Found a faulty 560uf/400v
electrolytic cap in the POWER Supply Unit. Replaced a working PS unit,
the symptom remains the same. The components ( except opamp TL082 and Logic
IC 4049 ) listed in question P414-7 and P210-1 have been cold-checked and
found okay.

Since the P/S swap
was no help, try replacing IC801 = 4049B logic IC, and check the fuses PS500
(SOC1600 = 1.6 Amp) and PS501. If no help, check if the flyback rings
bad. If a new FBT is needed, see if Electronix has 8-598-929-00 in
stock, before resorting to Sony.




QUESTION NO.
P101102-2: KDS VS-7 monitor FCC evokd-1730 had a blown fuse. I
replaced the transistor and fuse which gave me the start up voltage but the
high voltage did not come on. I found the HOT shorted, when I replaced
it I noticed some resistors getting hot. I removed power and checked the
board more closely and found R-901, R-902, and R-904 burned beyond
recognition. Also, ZD - 901 did not read like I thought it should. I
did not find anything else that seemed to be bad.

The flyback is
defective, and must be replaced, or it will burn those resistors again.
The FBT# KFS61411A should work; Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is one
source. R901 = 27K; R902 = 12K; R904 = 12K. Since R904 burned, suspect
IC401 may also be bad.




QUESTION NO.
P101102-3: Nokia 447e monitor dead. Replaced t24 (irf9622), now
there is a wide vertical line. Checked fm2529 6331 it shows 3.7 ohm
(it's a coil after all).

Check the value of
R224 (0.47 ohm). Check several tiny SMD transistors, locations like T60, T65,
etc, near the flyback. They are marked 3F or G3F, and are BC857, PNP
types. Inductor M3 usually will have shorts between some of its
windings, if it is bad.




QUESTION NO.
P101102-4: Apple Macintosh M3502 monitor. I need the value and
power rating for R113 located on horizontal power deflection circuitry.
The resistor is burned and transistor V104 is shorted.

R113 = 10 ohm/3
Watts. Also check the 2KV polypropylene capacitors, C108 = 0.011 uF and C106
= 0.0056 uF; R102 = 12 ohm; R109 = 22 ohm; R122 = 2.2 ohm; V105 & V106 =
MUR8100E.




QUESTION NO.
P101102-7: Panasonic Panasync S110i Chassis 21HV12S Model TX-D1F64MA
monitor. Has vertical white line signal ok, yoke ok came in with
shorted h/def transistor Q555 (2SC5423), used 2SC5047 problem remains.
Have reviewed questions P311-4, P61402-7 & P60602-5, very similar in most
cases but not exactly the same. Secondary voltages ok. Suspecting
D606 Sanken RP1HN special build reads high impedance, is this correct or
going in wrong direction? Q881, Q549 & R890 are also ok.

Beware of false
board numbering. Q861 is not a transistor but an 800mA semi-fuse, after
replacing this the 185 volt rail was restored and works fine with 2SC5047 a
little bigger physically but angle the 6.8 ohm resistor to fit.

A Sanken RP1H is a
2KV diode, and its forward voltage is 6 to 7 volts, so many meters will read
it as open-circuit in the forward direction. First, check the P/S secondary,
on the 185 Volt supply, and see if either R861 (0.33 Ohm, 1/2W), or the
microfuse at location Q861 (TO-92 case, UN11008 = 0.8 Amp fuse), are open. If
the 185 Volts gets to Q881, after all, see if Q881 has gate drive. If
no, check IC850. If Q881 is getting gate drive, and providing B+ voltage to
the collector of Q555, after all, see if Q555's base has horizontal drive
from IC580, via Q549; also check R554, D555.




QUESTION NO.
P100402-4: Gateway monitor EV500B - White raster with flyback lines on
screen.

Suspect no voltage
to the tube cathodes which is an 150V line derived in the power supply via
D922 and Q924.




QUESTION NO. P90402-6:
Gateway EV900 monitor. Initially R573 and VR501 burned. I
replaced them and D315. Now, R539 is burned and I need the value.

On a similar Mag chassis, R539 is 3.9K ohms.
When these components burn, the flyback is defective and must first be replaced,
or they will burn again.




QUESTION NO.
P100202-8: Acana Professional 165p monitor FCC IIB TC1 shuts down if
any of the front buttons are pressed.

The Eeprom, U602, may need replacing. If a
pre-programmed chip is not accessible, try rv6llh.rsuh.ru/flesh/081001/tvm-as5s(93lc66).zip for program
information. If replacing U602 is no help, the
processor U601 may need replacing.




QUESTION NO.
P100302-1: Sony CPD-200SX monitor shuts down after several hours of
use, then cycles on and off, hear relays clicking with on off cycling.
Cooling with fan used to extend use time, but is no longer effective. Visual
inspection hasn't revealed any loose connections or burned parts.

There may be
bad/intermittent solder joints on the main board, that need reflowing.
Start nearby the microprocessor. Tapping/flexing the board may give a
clue. Also, the 3842 chip (IC901, KA3842) is high failure in this
chassis, and perhaps yours has become marginal. Try freeze spray on it,
or replacing it with another 3842.




QUESTION NO.
P100302-2: IBM 6558-03/U monitor made by Sony displays only lower half
which shakes or is very wavy. Changed vertical IC, did not help.

The common cause of
such symptoms in the Sony N3 chassis is a defective IC007, CXA2043Q, Sony
p/n# 8-752-078-46.




QUESTION NO.
P100202-2: Acer 54el monitor FCC JVP7154E. Checked Q317 (F2161)
shorted and replaced for a new one but after switching ON, got display and
after a few seconds the Q317 burned again. Checked other component is
ok.

First, check that
L304 is not shorted/burnt, or rings badly, and retains over 0.6 mH of
inductance; if no, replace L304. Also check D316, D317, Q310, R214
(15K), C326, and disk cap C335 (220 pF/2KV). If C335 is at all suspicious,
just replace it. If R214 is bad, also check IC201. Finally, if the
above are all OK, check the flyback for shorted windings.




QUESTION NO.
P100202-7: NEC V920 Monitor. Need Flyback VCC resistor value
(R31A) color not recognizable looks like 0.--?? ohms 1 watt fusible, silver
middle code only readable.

R31A is 0.33 ohms
fusible (flameproof) 1 watt. Also replace caps and resistors on FBT
supply back to secondary p/s especially 0.22 ohms 2w will be partially
open.

In NEC chassis#
N9902, R31A is 0.33 ohm.




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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:06 am





QUESTION NO.
P100102-2: Sony CPD-200GS monitor had a too low filament voltage
because of a bad electrolytic capacitor. Now the top edge of the image
is bowed upwards (about 1/4" at the center). The bottom edge is
straight. How do I adjust this? There are no user adjustments for this on the
front panel.

Clean any pots on
the adjustment board on top of the yoke. Also, check around the yoke
for a piece of metal (possibly cut off a component that you replaced) that
may be stuck to the yoke through magnetism. If there is a small metallic
object near or on the yoke, it will disrupt the magnetic field around the
yoke, thus causing an anomaly in your deflection geometry. You may also
have an internal short in the yoke itself.




QUESTION NO.
P91702-5: We have a batch of HP D2826 monitors FCC A3KM079 we are
refurbing. All have either low brightness/contrast problems or micro
control (digital screen control) not working properly or erratic. These
monitors appear to be made by Philips. The brightness can seem to be
corrected by bumping up the screen master brightness adjustment on the FBT
but it seems not to help the contrast range much and washes out the color
some. These are fairly new units that were not used much so tube
deterioration is not likely. As for the screen controls (size, width, etc.)
we have no idea.

Replace the blue 3-pin crystal that controls
the microprocessor. Common fault. To activate service menu hold
in the Select button when turning on.




QUESTION NO.
P92602-2: Proview Technology 772 (200-100-pr98e) monitor. Original
problem was Q502 mosfet, R521, R520, ZD502 burnt or open. Replaced
Q502, resisters,18v zener and IC502 KA3842D. No when unit is plugged in
a ticking sound can be heard. VCC to IC502 varies from 11vdc to 14vdc
the ticking sound is about every half second to second. Checked ac
output from transformer T501 secondary and the 55vdc pin 9 is at least 75vac
and dc from top of c527 is 2vdc pulses in synchronize with ac pulses from
transformer. Keep in mind the set cannot be turned on at unless c527 is
removed. If removed too long it will take out next cap in line
(C527). I have found a mistake in CKT prints, R605 is not 1.2 k ohms it
is actually 10k ohms 5%. What should be the time duration of the ac
pulse when the set is just plugged in not turned on? There is no brown
glue around FBT or any other ckt. The only glue used is a white silicone type
on some components.

The rapid ticking
and voltage cycling suggests an overload or short somewhere, possibly on the
55V supply. Since C527 is on the 55V supply,. Check if D508 is leaky or
shorted. Also, Q630 is fed from that supply, so check if Q630 is
leaky/shorted, as well. If Q630 is bad, also check L603, and replace D632 and
C635.




QUESTION NO.
P92602-3: I need an equivalent or the manufacturer of a Targa AT897D
("product name" TM4296-1).

This monitor is an
Actebis brand. If it has an FCC ID Number, you can find it from the
following URL just type in first 3 characters.
http//www.fcc.gov/oet/fccid/. The following URL has a spec for the
monitor http//www.targa.be/fra/monit04.htm.

I believe this is
equivalent to the Amtran AT897D, FCC# MDZAT897, marketed by Amtran Technology
(Taiwan) under several brand names. If there is no FCC number on the label,
another clue is, the boards in Amtran chassis use an extra letter in their
location designators, unlike most manufacturers. For example, ICA01 (an IC),
CG31 (a capacitor), RG22 (a resistor), DH08 (a rectifier), QH05 (a
transistor), etc.




QUESTION NO.
P90302-8: The image size of Tektronix TX-D1F63R monitor (Chassis
Panasonic 21HV10S) is too big to fit screen as a sudden event. An
adjustment via OCD is not possible (range too small). Image is relatively
sharp and clear at slightly decreased brightness.

You should be
looking for a coil that has changed in value, or the center core has dropped
to the bottom of of the coil.




QUESTION No.
P91902-7: JD144K monitor has no image. Flyback produces an acute
sound, burns the resistor R441 (1K). Flyback measures OK. HOT is
Ok. The resistor connected R441 this to leg 7 of flyback, this leg does
not have continuity with any of the other exits of flyback.

When R441 burns,
the cause is usually a defective flyback. Often, the usual flyback
measurements will not detect this kind of fault. Pin 7 should not exhibit
continuity to any other pins, due to isolation by the internal rectifiers.




QUESTION NO.
P83002-5: Relisys TE 770 monitor. When switching on power the
indicator keeps on blinking (power LED). Replaced shorted Q951 (IRFS
630) and within a few minutes it blows again.

There is a
high-voltage (200V-250V) electrolytic capacitor, connecting off of FET
Q951. Check this capacitor, it is probably the culprit that is damaging
Q951. Also check the associated rectifier for damage, as well.




QUESTION NO.
P90402-2: Viewsonic 17PS Model 1786PS monitor. I need
the part number for R802 which is burnt. Looks like a varistor.

I don't have the
part number. However, I can give you the marking on the MOV (R802) if yours
is burnt too badly and you can't read it. First line is
"120", 2nd line is "M" logo (Motorola, it could more
likely be Meritek) followed by "6N22", 3rd line is "17".

I just took apart
such a monitor and found that the 120-6N22-17 part was rather well burnt.
After comparing the M logo to this website
http//www.elnec.com/ic_logos/ic_logos.htm#M which lists IC manufacturers and
their logos (a very handy bookmark), I determined that the part is made by
Matsushita. Apparently these MOVs work as surge protectors, but if they
get hit with too many surges they fail.

I believe this part
is an NTC ( Negative Temperature Coefficient ) Resistor. Otherwise
known as a Inrush Current Limiter, it is used to limit peak current in the
AC/DC switching power supply when the monitor is 1st powered up.
http//info.digikey.com/T023/V5/SectF.pdf Page 23. Don't know which
specific one is a match.




QUESTION NO.
P91702-9: Samsung CMH 7379L monitor. Need value of Q405.

Q405 is VN0606M, a small logic-level
N-channel Mosfet (TO-237 case). The VN0606M itself is listed by LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
and by Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] Also, Digikey ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists two
Zetex Mosfets, ZVN4306A and ZVN4206A, that might
substitute, despite their having TO-92 style cases.




QUESTION NO.
P91602-7: Proview 770M monitor, changed burned Q630 and number of other
components. Picture is too wide and pincushion at maximum (corners further
away from center). H-size, pincushion and trapezoid are unadjustable.

Not sure of board
ID number but you will find a feed diode next to flyback towards middle of
board standing vertically on a heat sink. It will either be short or
leaky. If not check the free standing transistors close by.




QUESTION NO.
P91602-1: Mitsubishi Diamond View (1772E) monitor FCC JVP7276E with a fault
that is shown in the archives where the resolution is mentioned as being
"The usual cause is a bad C327 = 220pF/2KV. This fault can also
damage HOT Q302, Q301, IC201 = TDA4858, ZD210 = 5.1V zener, R326 = 3.9K, R328
= 4.7K, R329 = 10K, J013 (3 Amp microfuse)". I replaced all of
these except Q301. I cannot locate what it is in my equivalence
books. I used the first NPN transistor I found and the screen fired up
but the PSU made a squealing noise that is affected by width (ie goes away
past the outter limits of screen or when shrunk to a certain size or
smaller). I found a shorted 4.7ohm R304 and when replaced the PSU goes
quiet but the left of the pic is in the centre of screen with some wrap
around and the OSD is much smaller and squashed into the top left 1/4 of
screen which turns into garbage if you try and adjust anything using
it. Also HOT Q302 gets really hot. All I can think of is Q301
needs to be specific.

First, the Acer
schematic shows R304 as 0.47 ohms, 1 Watt, not 4.7 ohms. Your 4.7 ohm
replacement possibly has caused Q302 to overheat, due to poor base drive. The
usual Q301 is a FET, BSS89, not an NPN, although on many Acer boards, the
Q301 lead locations are mis-marked, as "BCE", despite it's being a
FET. Some substitutes for BSS89 are BSN254 or ZVN4424C. Also, a BSN254A or
ZVN4424A (pinouts SGD instead of SDG) could work, if their leads are
re-arranged. Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists BSS89 and BSN254A. Digikey
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists ZVN4424A.




QUESTION NO.
P91002-3: Mag DX1595 monitor IAWDX15FG, the picture is too wide in vga
mode (text mode, 640x480 60Hz etc.) and expanded in the center. All
adjustments work but when width is adjusted to minimum the picture is still
too wide. Checked the board for dry joints etc. Other modes work
fine.

Check S-Correction
Capacitors & Fets plus Fet Drive.




QUESTION NO.
P91002-6: Nokia 447Xi monitor, FCC IEY447K had short circuit in HOT
T602 (=BUH1215). What else could be broken?

Check also
T601=IRF9540, T615=2SJ306, R639=0,56ohm/0,5watt flameproof and smd components
from the other side of the pcb nearby T601.




QUESTION NO.
P91102-1: Need a type or value for Q302 and ZD301 in a AST 7L
monitor.

It sounds like this
AST 7L is the Capetronics, not the Samsung, chassis version. In the Capetronics
chassis, Q302 is IRF630 and ZD301 is a 15 Volt zener. Often, bad
connections on D303 cause such failures, so resolder D303, and add an
extension wire to its lead, if the lead doesn't reach all the way through the
PC board.




QUESTION NO. P91002-7:
Fujitsu 772M monitor. I need the value for R634 and D634.

In the similar
EMC/Proview FCC# IJE772 chassis, R634 is 22 ohm, and D634 is a 1N4148 signal
diode. With these components bad, I would also replace superfast
rectifier D632, the FET Q630, and C635.




QUESTION NO.
P90402-4: Viewsonic g790 monitor is dead. I read 0 volts between
source and gate of FS10KM-6 power MOSFET but I read 170 V between source and
drain.

Check supply
voltage to IC901 pin 5 0V pin 7 above 17V to start stay above 12V to keep
working. If supply missing check R903 & R904. If these are
OK, check that Q903 has not fired it is an SCR with zener on gate to Pin
7. If the voltage on pin 7 is pulsing check for shorts/overloads.




QUESTION NO.
P82202-8: Philips monitor CM0700 A3KM043 in Apple 14 AV has a small
slot image in center of screen 6 inches wide 1/4 inch high. Flyback OK,
vert IC OK, HOT OK, changed caps, 2 x 1 ohm resistors & 1 x 4.7k half
watt. HOT running too hot and darlington transistor on same heat sink very
hot. Going into shutdown when signal applied. Have swapped good flyback
no effect.

The cause was a
totally open tube connections, replaced with new tube and unit works
perfectly. Items replaced were; 7916-IRF620 or equivalent,3915-4.7kohms
half watt 3637-1ohm half watt, 3152-1ohm half watt, flyback is HR46126
(Diemen)and the tube to suspect is Philips M34EDC13X.




QUESTION NO.
P82102-1: Compaq V500 monitor that I had to change the CRT, now I need
to adjust the colors. How do I get into the service mode.

This unit is made
by Samsung. You need the Samsung version of DAS software and interface
to re-adjust.




QUESTION NO.
P83002-3: HP-2842A Monitor LG p/n 6870T210A10. I need the part
number of IC 903 in the power supply section.

If your HP is LG
chassis CA-64, or is FCC# BEJCB910, it is similar to a LG Studioworks 910SC,
in which IC903 is TOP223Y, LG part code# 0IPF223000A. Aside from LG
distributors, LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists TOP223Y, on-line, in the
US.




QUESTION NO.
P83002-7 Samsung 400nb monitor chassis cka4217, IC602 (KA2H0880) has a short
between VCC and GROUND. I need info and sub for this IC.

KA2H0880 is Samsung
regulator IC; a Samsung distributor may list this IC, as Samsung part#
BH13-10334H. For a substitute, you could try KA2S0880. In North
America, KA2S0880 is listed on-line by LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] among others.






QUESTION NO.
P73002-6: Samsung NB 400 monitor, when shutting off it decays too slow
causing a burn spot on the phospher in the middle of the screen. I thing is a
CI ka2s0880.

KA2H0880 is Samsung
regulator IC; a Samsung distributor may list this IC, as Samsung part#
BH13-10334H. For a substitute, you could try KA2S0880. In North
America, KA2S0880 is listed on-line by LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] among others.




QUESTION NO.
P82802-5: Viewmaster KFC CA1515DS monitor. Need value of R138
near FBT fried due to bad joint on flyback reads 7.5 ohms.

R136 is 10kohms
half watt.




QUESTION NO.
P82802-1: Sun GDM-5010PT monitor FCC AK8GDM500PS. The picture
distorts on upper side, when I adjust it with trapezoid control, it suddenly
change the distortion to the lower side. It happens same when adjust
pincushion and vertical height. The H. size and position adjustment are
ok. I re-soldered deflection board but no help.

A defective IC007 =
CXA2043Q is the usual cause of this fault. Change that chip.




QUESTION NO.
P82202-4: Samsung400nb monitor, chassis cka 4217, is dead and the power
LED is not lit. I took measurements with tester and there is tension in
C617, primary transformer T601 but the rest of the circuit has no
volts. The relay does not turn on because there is no supply on the
Q601, the device TH601 seems to be in short because there are 0 volts among
their pins. I replaced burst photocoupler OPT601.

Check to see if the
power supply chip IC602 has supply to pin 3. If not check R616.

A burst
photocoupler implies a serious overvoltage problem. Since this device couples
to both primary and secondary sides of the circuit, any overvoltage might
have come from either side. If from the primary side, probably IC602
has shorted, and needs replacing. If so, also check zener D603 for
damage, and check components connecting to the photocoupler. If the
overvoltage came from the secondary side, I would first check T601 for
shorted windings, and then check components on the +13V supply, from pin 13
of T601, leading up to the photocoupler. Also, IC601, and possibly IC604, may
need replacing, and check that the values of resistors R605 and R609 are not
off. It is normal, for the "TH" device to have hardly any
voltage across its pins.




QUESTION NO.
P82802-8: Compaq 1210 model PE1041 monitor. I need the part
number and source for IC902 (STRF6676).

http//www.donberg.ie/descript/s/strf6676.htm.

STRF6676 (or
STR-F6676) is a Sanken regulator IC, rated for up to 900 Volts. This IC
is listed on-line, by Dalbani in the US ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] in Europe by
Donberg ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and in Japan ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P82802-4: Gateway EV700 monitor, the DC voltage on the HOT collector
varies from 75 -5 volts. The flyback pulse small with lots of
ringing. The base pulse comes up then shuts down and repeats every 3
seconds. Also the pulse regulator 160, and 70 volt lines, are down to
85 and 41 volts respectively. I replaced the HOT transistor, no
change. When the collector of the HOT is removed, the B+ to the HOT
goes to 159 volts. The 160 and 70 volt rise to normal. But the base drive
still comes up then shuts down and repeats every 3 second.

Check any diodes
connected to the FBT & the circuits they feed. Run unit with B+
disconnected & feed 30V into B+ pin of FBT must have capacitor to Gnd on
your psu O/P. You can now run unit and look at wave form on collector
if you have ringing desolder any supplies provided by FBT ie G1 etc and anode
cap but place away from unit and in an insulating holder, if collector is
still ringing then FBT is duff this monitor is made by LG and has a history
of FBT failure.

Gateway model EV700
uses many different chassis, including LG chassis codes CA-38, CA-48, CA-65,
and several Mag chassis, as well; you need its FCC or chassis code to
pinpoint it. But, if yours has 160V and 70V rails, I suspect it is LG
chassis CA-65, FCC# BEJCB775B. If so, a bad flyback (LG 6174Z-1012
type) is common. You may need to change the fly. Though a less frequent
fault, since they are cheaper than a fly, you might first check if 12V and 5V
regulator IC's, IC925 & IC923, are failing under load.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:07 am







QUESTION NO.
P82802-3: Compaq V75 model 624T monitor ticks once for a while, and
more when turned on longer time. The picture will disappear for one or
two second when it ticks. I checked and re-soldered main PCB and no help. The
ticking sound likes a soft spark noise.

That is the FBT
breaking down internally, very common on these units.




QUESTION NO.
P80202-10: Gateway EV700 monitor using an LG chassis, the screen is
fine except for ghosting, there is no horizontal jitter, just perfect
ghosting like 3D effect to the right of each character. I checked the
video amplifier and components around it.

With what you are
saying it is not ghosting it is ringing so you should be looking at the
flyback transformer damping. It will be difficult unless you can
scope all the lines for a stray pulse. Look for open resistors and
capacitors in the line drive and output.

To answer my own
question, it turns out that the cable was at fault, I used an extension cable
which seems to work well normally but with some monitors including this one
it seems that a good quality cable is required.




QUESTION NO.
P72302-3: Apple M4868 monitor. Customer says after a half hour picture
gets blurry with a line thru it. What I see is a light horizontal bar 1/4 in.
wide across the middle, and the horizontal convergence goes out slightly on
the lower half only. I checked caps and other components in the convergence
section and replaced the vert. IC with no luck. When I turn up the screen there
is about two inches of retrace lines at the top that are brighter than the
rest of the screen. They have color separation also when everything goes bad.
The problem shows up in under a minute from a cold turn on.

Check secondary p/s
caps, had similar on LG / Apple M4436. Replaced C952 10uF 100volts,
this one had good 640x480 but on 800x600 showed the lines you mention when
hot would appear all resolutions.




QUESTION NO.
P72502-7: Gateway 2000 CS1776LE monitor FCC IAWDX17F. I need the
values of C170, Q117 and R193.

If the components
mentioned are merely missing from the board, and a jumper wire had been
installed between the C and E positions for Q117, then this chassis received
Mag's factory modification, done in later production runs, which eliminated
Q117, C170, R193, as well as D121, D122, D123, and added that jumper.
This modification can be done to the original boards, if those components are
bad, obviating the need for their values; also check the usual problem items,
like L105, C120, C123, and R177.




QUESTION NO.
P72402-3: Viewsonic 17gs FCC gs933008 monitor is slow to get vertical
deflection when first turned on, but otherwise works fine when in 640x480 @
60hz. Switching to 800x600 @ 75hz and it loses vertical deflection
altogether, then at 1024x768 @ 60hz, it works again, but picture is
shaky.

Check/replace the
capacitors on the CRT board, especially C215 and C212.




QUESTION NO.
P72402-5: Diamond view 1772e monitor (aka Acer 7276e I think). Both the
boards in the monitor are Acer branded. The picture on the left hand
side of the screen shakes from left to right quickly, intermittent
fault.

If it's like the
Acer 76e, replace (don't check) disk cap C327. In the Acer 76e, its
value is 220 pF/2KV. A 3KV-rated, and a high-quality dielectric type (X7R or
Y5P), are best. After that, re-flow generally for bad solder; don't
miss checking C312, T303, and R347.




QUESTION NO.
P73102-7: Applevision 1710 monitor. I need the value of
RP49.

RP49 is smps start
up ptc thermister which if ok should read 4.8 to 5.4 kohms at room
temperature.




QUESTION NO.
P71702-10: Viewsonic e771 monitor has no power. Replaced shorted
Q406.

Transistor Q406 is
used for Hor centre so it only creates a small DC shift in the line
stage. As it is fairly well buffered, for it to short suggests a major
failure in the horizontal stage, I would check the flyback.




QUESTION NO.
P80802-1: HP A4331D monitor with Sony Trinitron Tube. When cold
everything works fine but after warming up the picture starts shaking
slightly vertically.

Replace IC913 =
TDA9102C, on the N board; it has likely become thermal.




QUESTION NO.
P80802-6: Compaq V70 model 621 monitor FCC A3LCGL777. I need the
value of R632. Is "Samsung CGL777" correct model name, or it
is better known as other one?

This Compaq is
similar to a Samsung SyncMaster 700P, CGH7609T, FCC#A3LCGL777. I
believe R632 is a 10 ohm fusible type. Also check/replace Q639, R617,
and C641.




QUESTION NO.
P80802-9: HP D2835 monitor. Looking for a cross for the vertical
driver, number on part is C5088.

C5088 is KSC5088,
not the same specs has 2SC5088. You can get this from LJ Enterprises.

KSC5088 (Samsung)
is the full number. In this chassis, substituting 2SC4924 for KSC5088
has worked, in the past. Also be sure to check/replace electrolytic
C414.

HP can be made by
several manufacturers. I presume C5088 is a transistor which suggests a
2SC5088, this though is a surface mount high frequency device working at UHF
frequencies. Only other would be if Samsung and its KSC5088 an in house
number of unknown specs.




QUESTION NO.
P80502-7: Proview PS-560 monitor, FCC IJE-564. Looking for the value of
D625.

The schematic for
FCC# IJE-564 shows D625 as 1N4148.




QUESTION NO.
P80702-1: Proview 770m monitor. I need the value of r672 as it is
cooked.

Proview model numbers are ambiguous, but if
your unit is FCC# IJE770, then R672 is listed as 39 ohms, 1/2 Watt.




QUESTION NO.
P80702-10: Samsung syncmaster 400Nb monitor, I need a sub for the
optocoupler part number l 9805.

The 'L' is the logo
for LiteOn, and 9805 is just the date code; the actual part no. should have
been beneath these characters. But if this is a Samsung CKA chassis, and the
optoisolator is at location OP601, it is listed as a LiteOn LTV817M-SM.




QUESTION NO.
P80602-10: ViewSonic 17EA monitor changes color sporadically.
CVA2419T is not available in this country any suggested replacement for this
IC?

LM2419 is
pin-compatible with CVA2419T, although it is slightly slower.




QUESTION NO. P80602-2:
Samsung 17Glsi monitor with no high voltage. Replaced Motorola 16212
Q502 (Short) and open R505 (1.8 Ohm/2W). Now I can hear the High
Voltage kick-in and being drop continuously.

First check if
Q503, D509, C505 are also leaky/bad. If these are OK, check if there is a
defect in the flyback transformer, or if the CRT itself is internally
shorted.




QUESTION NO.
P73102-9: ctc203 monitor is dead. Do I need an eprom and do I buy
it from del bony?

Any number of
things will make a CTC203 not power up. The EEPROM is a possibility,
and yes you can buy it from Dalbany 1-800-325-2264 in Miami, Florida.
There are lots of common component history failure repair tips info at home.mindspring.com/~wa6ati
then click on "TSS log for RCA CTC203"
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P80502-9: IBM 6547-0BN monitor. I am looking for info and
possible replacement and/or datasheet for a HOT marked "SEC
C5088".

"SEC
C5088" stands for Samsung Electronics Corporation 2SC5088 which many
electronic supply stores can carry.

This device is
KSC5088, formerly made by Samsung Electric Co. (SEC). It is rated 1500
Vcbo, 800 Vceo, 8 Amps (15 Amp surge), 50 Watts, Tstg < 3 usec, Tfall <
0.2 usec, no internal damper diode. Possible substitutes include NTE2324,
2SC4923, 2SC49244, 2SC5299.




QUESTION NO.
P72202-6: Toshiba D1566M-01 monitor blinks when lighting, the
horizontal out is well, but I found a Tmost Fet 6.0 amp 200 volts in
short. I need a substitute.

There are many
(about 10 possible replacement MOSFETS) MOSFETS that would work, ECG, NTE has
a free downloadable cross reference software at [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P71102-2: Tatung C7BTR monitor has s/c HOT type 2SC5386. I have checked
for dry solder joints etc.

Check if C430 has
bad ESR or value.




QUESTION NO.
P80102-3: Sony CPD-200GS (SCC # L07A-A) monitor takes approximately 15
minutes to show a picture. HV is fine and the monitor stays on and
eventually shows a good picture.

Check if the heater
voltage is low at first. If so, check components in the heater supply,
like C632, D615, switch transistors Q605, Q606, & the switch signal from
pin# 24 of IC901.




QUESTION NO.
P80102-4: HP D2846 monitor, picture is keystone-shaped, narrow at
bottom, full horizontal deflection at top, and confined to the upper half of
the screen. After 30 seconds or so, monitor loses sync and shuts off
with yellow light. Yoke tests good. I suspect this is a Sony chassis.
Major components test "good."

If your HP is Sony
chassis code SCC-L04G-A, this is a Sony 21N3 family chassis, check for a
defective IC007 = CXA2043Q.




QUESTION NO.
P80102-8: Compaq P110 630 monitor, green color is not working (the red
and blue still do). It is not the cable nor computer
hardware/configuration.

If your P110 is a
Sony chassis code SCC-L04 type, this is a Sony 21N3 family chassis.
Besides faulty video cables/connections, a faulty IC403, the video output IC
on the video ("A") board, can also cause this problem in this Sony,
so try checking IC403.




QUESTION NO.
P80102-9: Dell UltraScan 1000HS Model D1025TM monitor, I need the value
of R577 (located near in front of the HOT Q507).

If this Dell is a Sony chassis code SCC-L07
type, like the Sony CPD-200GS, the schematic lists R577 as 12 ohm, 2 Watt,
5%, fusible.




QUESTION NO.
P73002-7: HP D2817A monitor, FCC ACJ93312120, chassis HV5/HV5E.
Problems when switched on, picture goes on and off (probably HV too).
When warm, picture stays on, but it is still horizontally wavy on some
resolutions. Checked FET Q549 (drain), HOT Q550 (base) and B+ voltages.
B+ varies 40 volts when picture goes on and off. I looked for dry
solder joints too. Could it be flyback or HV capacitors?

In other brands
using the Panasonic HV5 chassis, similar symptoms to these have been caused
by bad capacitors, C215, C212, on the CRT board.




QUESTION NO.
P72502-1: Acerview99c FCC JVP7299C monitor. I need the value of
RF3929 and cause for it to burn.

I believe this is
the same as the 7279/7178 which is 22 ohms 3W. The coils in these burn
also. Check L304, all the high voltage ceramics and the flyback.

I show RF3929 as 22
ohms, 3 Watts. Also check Q313 and the flyback.




QUESTION NO.
P62702-5: Compaq S900 monitor after warm up, there is a pop and unit
high voltage shuts down. Wait a few minutes and unit will power back
up.

Check the two small
bipolar caps near the main switch on board, they were two 1uF 250v in series
can use X2 mains 0.47uF over both with some effort.

The pop is very
often the FBT breaking down in the blead/focus resistor chain, therefore the
eht sense usually taken from the bottom of this chain thinks that the EHT is
too high and shuts down.




QUESTION NO.
P72402-8: Acer 7176ie monitor has one white stripe horizontal.
The supply on the IC201 is normal but I am not sure that it is the original
IC201 because another engineer tried to repair it The ic is tda 4866,
is this the right one or should it be tda8351.

IC201 is TDA8351,
in the schematic; also check Q701 (2SB857) and R209 (1 ohm).




QUESTION NO.
P72302-8: Daytek Dt-1731D monitor. I need the values of Q901 and
R920.

Q901=STP6N60FI and
R920=470ohms.




QUESTION NO.
P71802-8: HP D5259A Monitor, I need values of burned R499 and
R400.

HP uses chassis from several different
manufacturers, in D5259A, but if this HP chassis is one of the Tatung chassis
(C7B), my diagram shows R400 = 2.2K and R499 = 1K ohms.

In the chassis C7B
the values of R499 is 1k , R400 is 2.2k




QUESTION NO.
P71702-3: Samsung SyncMaster 3 Ne CQB4147 monitor, cannot adjust
horizontal size. Related pot seems to be ok, no related circuit traces
open; but H position , side effect, V size/position work all fine.


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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:09 am





Check D407 and Q406
for excess reverse leakiness; also check for bad solder in this circuit.




QUESTION NO.
P71602-4: Acer 7178ie monitor FCC JVP7178IE has no video for the first
inch on the left side and small black lines appear streaking horizontally for
the first two inches. The width, height and H/V size all work. Where
the video starts on the screen it is very jagged.

Check/replace
ceramic disk caps, starting with C383 = 100pF/2KV. Also check C366
(1800pF/500V), C368 (22nF/2KV), and C317, C384, C385, C386 (all 220pF/2KV).
If not any of these, check if IC601 (UC3842) needs replacing.




QUESTION NO.
P71602-8: Sony GDM5001PT monitor, the raster is shrunk from sides &
it appears to have feedback problem and the raster is jumping some
times.

Changing IC007 = CXA2043Q.
Note, be very careful if desoldering and removing this IC, not to damage any
PCB traces; also, sometimes these IC's will need a DAS adjustment of the
trapezoid, etc, settings, after the IC replacement.




QUESTION NO.
P61102-2: Sun/Sony GDM20E20 monitor. I need values for Q507 and
Q508.

Based on a related
Sony chassis, I believe Q507 is IRF9630 (or similar type) and Q508 is
2SC3997.




QUESTION NO.
P62802-5: Mitsubishi Diamond Plus 70 Model TF-7700P monitor Chassis
HVA9AP/Z/PF has power to the low voltage circuits and is able to detect when
a signal is present. Power supply fuse is Ok. High voltage section does
not power up crt.

Check Q550
(2SC5406A), Q881 (2SJ306), tuning caps C553 (1200pF/1.5KV), C554
(2200pF/1.5KV), C556 (470pF/2KV), and FBT T601 (ZTPL03001A).




QUESTION NO.
P62802-3: Samtron sc428vs monitor, H.out transistor is burnt, I need
the the number of it.

The HOT is 2SD1878.




QUESTION NO.
P62702-1: IBM 6543-303 (G50) monitor, in mode 640 X 480 works fine, but
in dos mode the vertical raster is reduced 50%.

Check the system
control processor ST6370.




QUESTION NO.
P62702-6: CTX vl500 monitor. I need the value of a R717 and
C721.

There is more than
one version of CTX VL500. If this chassis is a 1569E, then R717 is 3.9K ohm.
If instead, it is a 1569S, R717 is 12K ohm. In both versions, C721 = 1
uF/50V, and in either case, your flyback transformer is also defective.




QUESTION NO.
P62702-7: Packard Bell 1512SME monitor. The horizontal output
transistor has gone. Which transistor do I need?

If the FCC# is
H4ICM15006 for this Packard Bell, then the HOT is 2SC5129.




QUESTION NO.
P62702-3: CTX 1875XE monitor turns on but there is no picture.
Suspect tube is not getting eht.

You need to
determine if the power supply is actually working. Remove the collector
of the HOT and bridge a 60 watt 240V globe to where the collector lead of the
transistors came from the the emmitter leg of the transistor. Take a DC
voltage reading on the circuit board at the collector hole. You should
expect somewhere between 112 -120Vdc (could be slightly higher depending on
the set) over volts at this point could cause beam current limiting to bias
tube off. If the voltage is present check the HOT remembering many such
transistors have a diode in parallel with CE and can show a forward biased
diode in both directions. Having established this check for a drive
waveform on the base of the HOT with the collector back in circuit. If
OK check for EHT by turning set on for a few seconds then off, using two
screwdrivers, slide one under the altar cap and use the other screwdriver to
discharge the tube to the back of the tube, if you have a nice splat assume
EHT OK at this point. Then check to see if the heaters in the tube are
lighting, if not chase the circuit back from the CRT board until you find
6.3V rms or within about 1-1.5 V using a standard multimeter. Note the 6.3V
rms is usually obtained from the secondary windings from the H output
transformer, using the flyback pulse. If none of these techniques prove
fruitful, check for secondary voltages from the H output transformer and the
switchmode power supply. It could also be prudent to check for the
presence of a video signal at the R,G,B cathodes on the CRT board. Also check
the tube grid voltages.




QUESTION NO.
P62402-8: Samsung 550b monitor, in power part, the IC hybrid dp104c
failure. I need its datasheet, parameter. Also its CPU
DM024.

The DP104 is
available from Samsung under the following part number BH13-00004A. Common
failure part. No schematics or datasheet since it is a Samsung Hybrid.
As for the CPU many revisions of this monitor exist and you will need to
provide the Model number from the back. It should look like DP15xxxx or
DT15xxxx. Only with this number can we find the right version.




QUESTION NO.
P62502-6: Compaq S500 model PE1112. I need value of R415
burned.

Compaq is notorious
for using different chassis under the same model number, but if your chassis
is a Daewoo 518X type, R415 = 10 ohms, 1/2 Watt, and goes to pin 7 of the
TDA4866 vertical IC, which is probably also defective.




QUESTION NO.
P62502-10: LG795SC monitor FCC BEJCB790 has shorted Q514, 515, 516, 531
& D528. Flyback checks out at 34.6KV, not sure about IC501 but has
1K. Resistor at J80 link and link where R555 (1K?) should be according
to my schematics. Is this assembly incorrect or is there a mod it just
means that the spark gap has no resistance from the flyback point? This is
the basic version or early version to the LG made Apple Studio Display M6496
17 inch.

That HV level is
excessive; it should be about 26KV in this LG model. A bad flyback
(6174Z-1024B or Y265382) can cause excess HV in this LG; the HV adjust is at
VR501.




QUESTION NO.
P62402-9: Acer 7277c monitor keeps switching on and off with no
display. I replaced burned R356 only to have it burn again.

It sounds like a
defective flyback transformer is burning the R356.




QUESTION NO.
P62102-8: Apple M3705 monitor has a horizontal problem. Replaced
burned RL163 but it burned again.

Try checking QL2,
QL12 = IRF9630, QL23 = BUH1215, and capacitor CL9. Also check that the
transistors are not shorting through their insulators to the heatsink.
Check the solder on the Horizontal yoke connector, in case bad solder there
had caused other failures.




QUESTION NO.
P62102-2: KDS VS-5 monitor, the red is gone. Tried adjusting the
red gain (digital), but nothing. The output (LM2406T) seems to be ok,
redid some solders with no luck.

If this VS-5 is
FCC# EVOKD-1510, first try checking the video cable for internal
breaks. If this is not the fault, try tracing the red signal, comparing
to the other colors, to find where red is lost. The RGB preamp IC should be
IC201 = MC13282EP, pins 4, 2, 6 being the RGB inputs, and19, 22, 15 being the
RGB outputs. These outputs go into the LM2406 at pins 11, 9, 8; and
output from pins 1, 3, 5, to the CRT.




QUESTION NO.
P62002-1: Sony monitor chassis SCC-L07B-A will not start, the led comes
on green for a few seconds then blinks orange. During the period of
time when the led is green the +B (which normally should be around 180V) is
around 160V and the +15V is about 8.5V, and when the led is blinking orange
the +B is around 150V and the +15V is about 6V. The monitor WILL start
if I use an artificial load for +B (a 60W light bulb) but the voltages are
all wrong +B is around 160V, -15V is -12.4V , +15V is 12.4V, +80V is around
+60V. If I start the monitor in this way then remove the light bulb,
the monitor remains on but with the same voltages described above. I
replaced the optocoupler, all the primary caps, IC601, IC604, D614, D612,
D622, D654, R628, R630 and removed D608 but the problem still remains.

Try checking the
filter capacitors on the secondary side, like C622, C621, C619, etc., for
high ESR, poor value, or leakage. If any are bad, also check if the
rectifier going to that filter capacitor is leaky/shorted. If none are
bad, try checking devices off the 180V supply, such as Q503, Q507, Q510,
Q520, ultrafast D516, and the flyback.




QUESTION NO.
P62002-9: Sony CPD-GF100 monitor is dim. There are no internal
screen voltage or sub brightness/contrast adjustments.

Those adjustments
are all done using Sony DAS software. You could check if the heater
voltage is low, if Q001 is defective, or if the CRT has poor emission.
Screen is controlled by opamp IC005, using Q001. If instead, the
problem is low drive to the CRT cathodes, check if inputs to pins 25-28 of
IC001 are too low. If these inputs are all good, IC001 may be bad.




QUESTION NO.
P62002-7: Dell Ultrascan 17FS-EN monitor (Mitsubishi TFS6705) has no
high voltage. On gate of Q603 there is an H-drive pulse of 500mVpp and
168V via T601 at its drain but it does not pulse. Are they good
values? I changed Q603 but it continues and I have not found broken
parts around it. All controls and power supply voltages are good.

Be sure the fan is
running at the correct (3300) RPM. If the fan runs too slowly, and its
pulse circuitry sends pulses too slowly, the monitor will shut down the HV.
Sometimes the fan's bearings just need lubrication; the pulse circuit also
can go bad.




QUESTION NO.
P62002-4: Wearnes VGS-1490G monitor is blurry and dim even with setting
the brightness & screen (at the flyback) to the maximum position. I
checked HOT C5149 and Power FET SSH6N80 it's okay.

Unless the heater
voltage is low, the CRT may be worn out (poor cathode emission).




QUESTION NO.
P61202-3: Viewsonic E-40 monitor is dead, LED blinks. If I open
ic ne555, set is on in normal but horizontal size is not right.
Replaced ic ne555, no help.

There are several
different versions of E40, but the output (pin 3) of the NE555 is probably
driving the gate of a MOSFET, via a resistor. Look off the drain of
that FET for a coil, and then an ultrafast rectifier feeding an electrolytic
filter capacitor rated 200 volts or more. Check if the coil is shorted
or has lost inductance, or if the rectifier is leaky in reverse or
shorted. Also check the filter capacitor for good value and ESR. If
these components are all OK, check if the NE555 is turning on the FET
continuously, rather than providing pulses to the gate, due to bad
component(s) biasing the NE555.




QUESTION NO.
P61402-7: Panasonic PL-70 monitor has no horizontal deflection.
Measuring Q550 gives nice waveform on oscilloscope. Bringing up
brightness shows vertical line 4 mm wide. I am using P-70 schematic as
it seems similar. R588 & R589 are ok.

Found the
deflection problem. 1st problem was scope, measurement probe was partially
broken, ( ground connector not connected sometimes) thus I had false
measurements. The real problem was J114 was open, this is actually
miniature fuse, rating unknown, maybe 1A. The reason for fuse blowing
was Q881, 2SJ306 was shorted.




QUESTION NO. P61302-11: Proview 572
monitor is dead, read short across Horiz. output transister, Q601.

Replace shorted
C635, 22UF@250 volt DC, connects to pin 3 of IFT.



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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:11 am





QUESTION NO.
P60602-1: EV700 monitor. Trying to determine a reason why
transistors Q719 and Q721 (2SK2134) are burning up. Q719 burned up
first and replaced, now Q720 is burning.

First, Gateway has
used several different LG and Mag chassis, as model EV700, so further
identification is needed, to pin down which "EV700" is your
chassis. But I suspect yours is an LG chassis, and FCC# BEJCS789, from
the FET references. If that is your chassis, these FET's switch the
different S-caps. It seems possible, that the peak AC voltage to the
drains of these FET's, via the S-caps, is exceeding the 200V limit for
2SK2134. Check for a bad winding from the flyback, T701, off pins 3, 4,
5, or a bad component off these pins, then follow it through SW701, to check
L702, and R757, R758, and the S-caps, then continuing on to L703, R759, D717,
and the horizontal yoke coil. Less probable, the 15V supply, for
driving the FET gates, has gone very high in voltage.




QUESTION NO.
P60602-5: Panasonic panasync S110 monitor chassis HV10S. The
lower part of the picture has become a very dense line in the middle of the
crt and there is nothing in the lower part of the crt. R482 (150ohm) has
overheated beyond identification.

Your R482 and R483
should have matching values (other models use 1.2 ohm, 1 Watt), so compare
R482 to the value of R483. Check if R482 burned due to an overload from
a shorted component off the vertical IC, LA7875, including the filter cap off
of pin 2, and check the vertical IC, itself, as well.




QUESTION NO.
P60602-9: Calima 17 CB6748SNT2 monitor FCC GBVCA6738SS. Hot
Transistor burned 2SC5302, any replacement suggested?

2SC4891 is a
possible substitute for a 2SC5302.




QUESTION NO.
P60602-10: I need value for R241 and ZD202 in MAG LX1450LG monitor. All
burnt beyond recognition.

R241 = 20 Ohms,
ZD202 = 20V. I'd also check Q303, IC303, and the values of R325, R335 =
33.2K, and R334 = 1K. Also check/replace electrolytics, especially C315,
C316, C335.




QUESTION NO.
P60402-7: Samsung 700p plus monitor has vertical deflection
rings. There are many randomly jumping vertical lines on screen.
On middle there is only few scanlines within black 1 inch stripe and on most
of lines are at bottom end of screen. Changed few caps at vertical deflection
circuit. No help.

I believe you are
describing vertical fold over. Check the Vertical output for the correct
waveform and correct amplitude. If the waveform is present but reduced,
the output stage is possibly intact. I had a similar problem with a TV,
the end result was that the Vertical deflection yoke had gone from about 14
ohms dc resistance to 19.5 ohms. eg., Increase the line resistance and the
deflection current will decrease. With the presence of the drive
waveform confirmed, either ring test the V yoke for shorts or check the
resistance for an increase.




QUESTION NO.
P60302-8: Acer jvp7279g monitor. What type of FBT or are there
any others I can use?

My notes show this
Acer's FBT, as part code 19.70044.011.




QUESTION NO.
P51402-7: NEC Multisync C500 monitor (JC-15W1VMA). No control over
horizontal width or pincushion/barrel from onscreen menu even though the menu
appears to function correctly. Screen picture OK but only 1/3 in
width.

Check for shorted
base emitter Npn transistor in horizontal drive stage. Also review
answer for Question P5002-10 Packard Bell A720 monitor which will explain how
these systems work.




QUESTION NO.
P53102-5: Dell 828FI monitor 800F series works fine until turned off
and back on, or reboot PC, than LED flash green twice as fast (blinks when
connected to non working PC and constant ON when computer is on) but no
video. Turn monitor off and disconnect from computer for about 5
minutes, connect again, turn on and everything works fine again until you
reboot PC or turn power off and on. When power cycled on off on I can
hear slight buzzing noise (very slight) like it is not enough power to kick
in high voltage ether on power supply or on the flyback. I replaced hot
Q406 transistor and the D403 with no effect, replaced C503, C606, C515
nothing changes. Replaced TDA 9109, it did not help.

The micom ic202
supplies OSD,to the video board.vert/horz sync to TDA 9109. According
to Samsung, check H/V pulses Pins 4 & 10 of ic105 NO check ic105 OK same
H/V Pins 20&21 ic202 NO ic202.The other ic is the E2EPROM ic205..There is
a reliability mod for this chassis. With chassis removed, clean the
lower edge of the bell CRT. Glue a piece of foil (3inches wide 10 long)
along the bell over-lapping the rim band. This is to prevent static
discharge from the CRT from damaging ic302 or the CPU. Many of the
common faults on this product are attributable to ic302.




QUESTION NO.
P52902-5: I need value for R935 in Daewoo Monitor 710B.

R935 is 82K ohms.




QUESTION NO.
P52802-9: ADI ProVista CM700 monitor is dead. Customer reported
smoke then died. HOT appears ok. Need values of R970, ZD 902 and
ZD903. All burnt beyond recognition.

In the schematic
for the ADI CM700, R970 is a 47 ohm, 1/2 Watt resistor, and ZD902 and ZD903
are both 36 Volt Zeners.




QUESTION NO.
P52802-3: Tiny 17N (CA-65) monitor, the PS 'clicks' (about 4 or 5 times
a second) for five or six seconds then trips (led blinks) and then repeats
this continuously. PS voltages are present but some low, Q719 seems to
get very Hot.

Check/replace L705, C735, D704, D705, D707,
Q706, and the flyback transformer. You may also need to replace that
Q719, if the overheating has damaged this FET.




QUESTION NO.
P52802-6: AcerView 54e has no green color (red & blue are normal)
upon powering up. The green color appears flickering after about ten
minutes or so, then the colors gradually/suddenly becomes normal and stays
normal until turning off.

Resolder the CRT
PCB, especially check connector P101 and the CRT socket. If this is no
help, see if there is an intermittent in the video data cable.




QUESTION NO.
P52802-1: Sony GDM20e21 monitor has horizontal retrace lines on a white
background with no video at all. I checked all solder
connections.

I believe you are
describing vertical retrace lines, these are not normally seen due to the
electron beam being blanked out during retrace period. Video signals on
monitors are directly applied to the cathode via the CRT board and a driver
transistor, from the video board in the computer. A quick check with an
oscilloscope at the base of the driver transistor will confirm the presence of
the video signal. A condition that will produce the symptoms you have
described, is when the screen volts have gone high. Most modern flyback
transformers have a screen volts adj as well as a focus adj. Try turning down
the screen volts to a suitable level to see if it has an effect on reducing
the retrace lines and restores the video. If this has some effect check also
that the B+ line has not gone high. Any increase in B+ will also
proportionally increase the EHT. Small electrolytic capacitors in the power
supply are the common fault for over voltage situation, so if the B+ is high
check them all.

First check/replace
IC420 = CXA1907S, the usual culprit. If not IC420, then check IC405.




QUESTION NO.
P52002-10: Packard Bell A720 monitor horizontal deflection decreases
with increase in resolution settings. Unable to adjust out with user
settings. Display only covers approx 80% on lowest res and aprox 40% on
800x600. Vertical deflection also increases at same time and is set to
minimum. Tried to test HOT but inconclusive.

A general rule of
thumb I use for solving this common problem with monitors: From the
front panel controls for H width adjustments pulsewidth modulation is used,
by varying the pulse width the resutant output is a variable DC voltage. This
DC voltage can be followed through to the emmitter of a transistor in the
H/drive stages. A variable DC voltage at this point will vary the gain of the
Horizontal waveform. So look for a shorted base emmitter in this area of the
circuit. The Horizontal transistor is OK, if it wasn't then the set would not
work.




QUESTION NO.
P52302-3: I need a cross for a H6NA80FI manufactured by ST, it is a
Power Mosfet that is used in the switching power supply of a Apple multiscan
15 AV Computer monitor.

STH6NA80FI is an ST
Micro N-channel Mosfet, in an Isowatt218 case, rated for 800 Volts, 60 Watts,
Rds < 2.2 ohms. Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing the
original STH6NA80FI, on-line. If a TO247 insulator is used, then STW7NB80,
listed by Mouser ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] could substitute. Or, IRFPE40 or NTE/ECG
2377, with insulators, might be tried, though these have higher capacitance
values.




QUESTION NO.
P52202-1: NCD nc782aa monitor FCC A3KM053 when powered up, just the
green light comes on. Checked the hot, it was good but monitor is not
getting voltage to the hot.

From the FCC# for
that chassis, try checking the value of R3570 (1 ohm), located by the yoke
connector on the main pcb. If R3570 is good, check the FBT.




QUESTION NO.
P52202-2: Gateway with Sony CPD15F1 Chassis was completely dead.
Replaced shorted HOT Q507 and SW REG Q503. Unit now powers up, but both
green and yellow lights flash after a few seconds with no raster.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:12 am





QUESTION NO.
P52202-2: Gateway with Sony CPD15F1 Chassis was completely dead.
Replaced shorted HOT Q507 and SW REG Q503. Unit now powers up, but both
green and yellow lights flash after a few seconds with no raster.


Try checking
Schottky D508, and check the boards carefully for bad solder joints, and for
cracked PCB traces & rivet grounds near heatsinks, transformers, etc.





QUESTION NO.
P52202-3: Gateway 2000 CrystalScan 1776 LE Monitor when powered up
there is a clicking noise coming from the main control board and power supply
board. I discovered L105 transformer was discolored and very hot to the
touch, I need the value.

L105 (Mag#
T*l-281-103-UO) has an inductance of 4.5 mH, and it should ring good.
Since yours is discolored, it is probably bad. For replacement, try Mag
Innovision, or suppliers like Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or LJ Components
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P52102-7: LG StudioWorks 775N monitor. Clicking relay with a
blinking green LED. Replace IC901 but is still the same.

Check Q706, Q719,
and D704 for leakiness or short. If not, try replacing the three voltage
regulator IC's, IC923 = 5V, IC925 = 12V, and IC304 = 8V, which may fail under
load. If no help, then replace the flyback, LG# 6174Z-1012B.




QUESTION NO.
P51602-5: Sony GDM-400PS monitor, red gun quits after about 30 seconds;
retrace lines show loss of red too. No other symptoms, cable tests
good. Not sure if chroma, driver, CRT.

Try checking at
IC407 = FA4111 (Sony part# 8-749-013-74). The red signal should input at pin#
1, at about 4 Vp-p, and output at pin# 3, at about 50 Vp-p, to the CRT.




QUESTION NO.
P51602-6: Tiny 17N monitor FCC BEJCB775B. The supply trips with
or without a dummy load when active, but remains rock steady at 160V in
standby. 11V rail as marked on the board down to 8V, but I reckoned
that would come up when the supply sync to line after start-up. The
line stages look ok on first pass, no shorts on ht rail that are obvious
either. I really need a chassis ID.

That FCC number,
BEJCB775B, gives your chassis ID. This FCC is for LG (Goldstar), and is also
used for the LG Studioworks 775N, LG chassis family CA-65. In that chassis,
start by checking/replacing the Voltage regulator IC's IC925 (12V) and IC923
(5V), and then checking/replacing the flyback (6174Z-1012 or similar).




QUESTION NO.
P51602-7: Radius Intelicolor 0461 monitor starts the HV for 3 seconds
then shuts down while the power and stand by leds are flashing. The 144
Vdc in Power supply from 145 V falls to 56 Vdc. The adjust led stays in
SIZE.

This Radius is a
Sony GDM-20E01 chassis. In that chassis, when the power & power-saving
LED's flash, and the SIZE LED is on solid, this is an error code for a
problem with the ABL (beam current) circuit.




QUESTION NO.
P51602-9: Hewlett Packard Ultra VGA 1280 monitor, there is no label on
the rear, so can't identify further. Pcb is labeled #code no
BH41-10308N. Other markings on the pcb are # CMG73*7 MAIN
PWBMP-6.3. The problem is that there is fold over e-w on the horizontal
scan, both left and right symmetrical about 1" either side. R427
is burnt beyond recognition. The picture is good except at the edges where
folded over occurs, there, it is de-focused slightly. There are no obvious
short/open caps or diodes around this area.

The chassis code
CMG73*7 indicates that this HP is a Samsung chassis, similar to the Samsung
Syncmaster 17GLi (CMG7377). In that chassis, the value of R427 is 1K
ohms, 1 Watt.




QUESTION NO.
P51502-6: Compaq Monitor P75 model 625, would not start up.
Replaced open R622,1.2ohms and shorted D615 (with a high current
diode). Monitor starts up and operates of input signal from base unit,
D615 gets warm, limited brightness control. What is the value of D615?
What could be causing D615 to warm up?

This Compaq sounds
like a Sony chassis. Is there a Sony FCC# or a Sony "SCC" chassis
code on it anywhere, like on the label or on the CRT housing? If yes,
it sounds similar to a Sony CPD-200GS, SCC-L07 chassis. If it's like the
CPD-200GS, R622 is 0.12 ohm, not 1.2 ohm. D615 is a 200 Volt, 4 Amp, 30 nsec
ultrafast diode. If you did not use an ultrafast diode, this could explain
your diode heating up. Possible substitutes for this diode include MUR420,
UG4D, BYV28-200, NTE576 or NTE619. Also, D615 could overheat if the filter
cap beyond D615 were bad; in the CPD-200GS, this cap would be C632. Other
components on the supply going to the CRT filaments for CPD-200GS, are pass
transistor Q605, and R637 (2.2 ohm, 1 Watt); the analogous components in this
Compaq could also be checked.




QUESTION NO.
P51402-10: Philips C2082DAS monitor. I need the value of C839.

If this Philips is
FCC# GZM1323, I show C839 as 470 pF/2KV.




QUESTION NO.
P51402-8: Nokia multigraph 445M092 monitor. T41 (2SJ307), D30
(UF5404) and R172 (0.47ohms) are burned. I measured D31, D32, D39, the 12V
SMD-Zener-Diode (Y2) on the backside between source and gate from T41.
They should be OK. I changed the burned T41, D30, R172 but they burned
down again after 5-6 hours.

Check inductor M3
for burnt or shorted windings.




QUESTION NO.
P50702-6: Dell D1025tm monitor (Sony CPD200gs) has a fuzzy
picture. The keys on the front are locked up. When I press anything but
the menu, I get a picture of a key in the lower left corner. The menu
will only let me move between two of nine menu choices. How can I
unlock it? Do I need the DAS software to do it? Dell could not find
anything about it and the Sony manual does not say anything about locking the
menu.

The Sony CPD-200GS
does have a "Lock" Option in its OSD Menu; perhaps the same
procedure is used in your Dell. Press the "Menu" key, use the
arrow keys to toggle Up/Down and Left/Right, to select the "Option"
Menu (at lower right), and then press "Menu" again. Several Options
will appear, including a Key Icon. Toggle up/down to the Key Icon, then use
the Left/Right keys to turn it off. Regarding the fuzziness, try going to the
"Screen" Menu (upper right), and adjusting the H or V convergence,
or the Moire.




QUESTION NO.
P50902-4: Apple Studio Display 17 [M6496]. A standard fault in
this monitor seems to be that something arches (assumingly within the
flyback) that can go on for a while until it blows up other parts and the
monitor stops working. I've got a bundle of these monitors that have stopped
working. What other parts (apart from the flyback) should be replaced? When
repaired by Apple their list of replaced parts show a diode, a rectifier
diode RL2, an 18 Volts zener diode of type MTZJ18, a 2K resistor, the 2SJ306
MOSFET and the flyback (6174T-13003C or 6174Z-1024B or Y2653820). The 2K
resistor is easy to find as there's only one on the print (R555), the flyback
and the MOSFET are also obvious but where are the other parts (what are their
part numbers)?

Besides the
flyback, check FET's Q503 = 2SJ306 and Q507 = 2SK2847. D502 is an 18V
zener such as you have described, used for gate protection on Q503, but also
check D505, the diode off the gate of Q507. The D503, off the drain of Q503,
is either RL2 or RL2A (Sanken ultrafast types); double check your exact type,
as RL2A is rated at 600V, 1.1 Amps, but RL2 is only rated for 350V.
Also check IC501, Q203, Q204, R547 (47 ohm), and the small diode connecting
to R555, which is D532 (similar in specs to 1N4448).




QUESTION NO.
P50702-7: Viewsonic 21PS monitor, FCC GSS933006 does not show any red
color on the screen.

A common failure
for loss of a color in this chassis is a defective IC1302.




QUESTION NO.
P50302-6: CTX 1769se monitor. I need the value of Q313, A TO 220
package has marking as top DD 54 bottom RC 7L4.

The TO220 device,
DD54RC, will be a Sanyo Damper diode, rated 1500 Volts, 5 Amps, Trr under 1.5
usec. But I would re-check whether this device was actually assigned as
Q313 (typically a HOT transistor), or whether it has a "D" prefix
location assignment.




QUESTION NO.
P50802-4: Sony cpd-200es monitor has no green color, red and blue
appear normal.

Replaced Q512,
irfli530, problem still existed. Final solution was a bad video cable,
pin 2 was intermittent unless cable was flexed 90deg to connector, cable was
replaced and the problem was solved.




QUESTION NO.
P50902-2: Acer 7277c monitor. I need to ID R330, R329, R365,
& Q322.

R329 = 240K, R330 =
80.6K 1%, R356 = 10K, Q322 = A673. Check Flyback, normally when R356
burns the flyback is bad!






QUESTION NO.
P40302-6: Acer 7277e monitor, no FCC came in with FR707 burnt, replaced
with a 1ohm resistor. Picture shows 3/8 inch wide black line running
from top to bottom, about 1/3 of the way across the screen from the left
side. Q312, Q318 running so hot you can't touch the large heatsink they
are attached to without burning yourself. It only takes a minute to get
this hot. I replaced C335 (220pf, 2KV) with a 330pf, 2KV (all I had to
try). Now after on for a minute, picture stabilizes to a normal picture,
but Q312 and Q318 are still VERY hot. Before changing cap, picture
never stabilized. Checked all diodes, and transistors in the area of
the pincushion circuit. Also all the electrolytic caps near
there. All power supply voltages appear normal, (used a schematic of
7276e which is somewhat the same).

Fr707 is on the 45v
line from the power supply area and this feeds q312 via L301. This
would be the first thing to check for burnt windings it should be 2mh.
Q312 goes on to feed q318 via q317 and from there to D305 via L302 the next
thing to check it should be 150uh. You might also check D318, and Q302.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:13 am







QUESTION NO.
P41002-10: Acer 1554 monitor, how do I set the color balancing?
These monitors do not have any internal adjustments.

If you mean by
color balance that either of the three main colors are too strong, you have
to replace IC101 lm1203 as this ic does all of the color processing.
Check pins 4-blu, 6-grn, 9-red, for signal level in and pins
16-red,20-grn,25-blu for signal level out. The voltage levels should be
very close to each other in each group.




QUESTION NO.
P41202-9: Acer 7277c monitor with a burned R356, I need the
value.

On my cct for Acer
7277e r356 is 10k and connects to the base of q322 which is concerned with
the ABL control. The other side of the resistor goes to pin 8 of fbt




QUESTION NO.
P41602-4: Acer 7277e Monitor. I need the value of R339, which
burned.

Rr339 is 3.9k 1%.




QUESTION NO. P
43002-8: Tiny A1770NSL monitor, the screen is too wide and bowed but cannot
be altered . Electronically altered but controls have no effect . All
other adjustments are o.k.

If this
"Tiny" model is a LiteOn chassis (FCC# H4ICM17007), try checking
Q423 and R411.




QUESTION NO.
P43002-7: Mitac L1564PD monitor. Transitor Q502 was removed by
previous repair workshop. I need the value of this.

In the Mitac
manual's parts list, Q502 is given as 2SD921.




QUESTION NO.
P43002-4: Dell D1025TM monitor, how do I adjust the screen controls ,
and the gain for the red, blue, green, (there are no pots). Is this
chassis a Sony? What is the Sony Model?

This Dell is
similar to the Sony CPD-200GS model. Service adjustments in that Sony
model are done with the Sony DAS software and interface adaptor. Using
the user OSD controls, brightness and color temperature levels may be
selected.




QUESTION NO.
P43002-3: Sony CPDE200 monitor has two horizontal thin, very faint
lines running the full width of the monitor spaced about 100mm apart.

This sounds like
the stabilizing wires for the aperture grille inside the CRT. These wires are a normal
item, and are described on page 13 of the Sony CPD-E200 User Manual.




QUESTION NO.
P41202-4: Magitronic C-SV1700PS FCC H4ICM17005. I need part # for
HOT Q424 and D407 also, where can I order the EEPROM I703 and the parts above
mentioned?

That FCC number is
a LiteOn, and in that FCC, the HOT is 2SC5150 and D407 is a Sanyo DD54RC damper diode.
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or B&D Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] may have these. Also,
if the HOT had shorted, see if there is an open 2 Amp microfuse on the board. Try
asking Nationwide about sourcing the LiteOn Eeproms.




QUESTION NO.
P41902-6: Techmedia TCM-1448G monitor FCC j4RTCM1448G. I needed
part number for Q507.

Q507 is BU2508DX; a
BU2508DF could also be used.




QUESTION NO.
P41502-6: Compaq V500 model 1111 monitor has a pulsating picture with
poor focus. Turn up G-2 then back down the picture stabilizes. If
unit is turned off, then back on the picture pulsates again.

Replace all
capacitors with 100v to 250v in H. section and resolder all h. out & v.
out areas.




QUESTION NO.
P41602-6: D2026T Ultrascan 20tx monitor has horizontal shake after
about 1 minute of warm up.

Resolder all
capacitors, TR, Diodes near flyback. Resolder crt board.




QUESTION NO.
P40202-7: Trigem monitor, without the HOT soldered (I unsoldered from
the board) the voltage (b+) on collector HOT is normal (110 to 130 Volt) but
when I soldered that HOT on the board the B+ on collector HOT and on the
power supply dropped into 30 Volt. What is the real type of this
HOT? Is it C4762 or C4770?

Faulty FBT or Short
pf in H. section.




QUESTION NO.
P41802-2: Gateway CPD-GF100 monitor has a foldover at bottom of
screen. By adjusting vertical position the foldover increases when
lowering displayed image. It appears as though image was a sheet of
paper curling upward from bott m reversing what is on front of the
reversal. By adjusting vertical size it will fit but with a tenth of
the screen black from bottom of image to bottom of screen.

Replace all
vertical out put capacitors and resolder all joints in vertical
section.

One cause for this
symptom, is a bad C653, a 470 uF/25V capacitor.




QUESTION NO.
P41802-10: Proview ps508 model 564px monitor FCC ije-564 is dead.
Replaced blown C635 (22 mf cap 250v) and shorted D675 with no change.

Replace all caps
with 250v near flyback and check dry sold joint. Resolder flyback and
all pf.




QUESTION NO.
P326-7: HP ultra VGA 1280 monitor has no picture. The flyback and
horizontal output are ok.

H. oscillator IC
faulty. Replace and also check 220pf with 2kv.




QUESTION NO.
P320-2: Compaq v75 monitor, picture jumps up and down fast. When
adjust g2 it stops. Switching it off/on, same problem again.

Resolder vertical section
carefully and replace all vertical output capacitors, especially main b+ of
vertical output IC.




QUESTION NO.
P319-5: NEC/Multisync 2A monitor, is dead. Green LED on front
panel does not light. Clicking sound coming from power switch.
Fuse is OK. Resistors, caps and diodes all check out. No signs of
heated components other than Q502.

Normally H.OUT
transistor faulty, replace with BU2525A or BU2508A and resolder all areas of
FBT.




QUESTION NO.
P41602-8: Acer AJ15 monitor FCC AMPJ511 the display has become very
unstable, it changes in horizontal and brightness cannot be adjusted.

Check for dry
solder on the crt board. Also resolder all connection joints with main
board.




QUESTION NO.
P41802-8: Daytek dt1536d monitor- ht arcing from top of lopt to core
blowing hot. All other components seem ok.

I suspect the
flyback (LOPT) is bad, and needs replacing. This model is also known
for getting bad solder on the flyback connections, which also can cause the
HOT to blow. A general solder check is needed, as bad solder can occur
all over the board.




QUESTION NO.
P41802-6: Acer 7178ie monitor. Found components blown Q321, Q314,
R363, RF3959, etc...need value of R363 and if possible loop diagram of
flyback. Resistor cooked but not obliterated, codes unreadable now
showing 12.7 ohms.

In the Acer 7178ie
file at rv6llh.rsuh.ru/shema.htm, R363 is given as 22 ohms, 5 Watts; it's in parallel with
a coil and a cap. There is an FBT diagram in the Acer 7178ie file.




QUESTION NO.
P41702-9: KDS VS-F14 monitor goes dim to almost black within seconds of
power on.

Sounds like a
component is starting to fail on the inverter board, that provides the high
frequency/high voltage AC for driving the fluorescent lamp. Unless it
is something simple, like one of the film capacitors on that board is
failing, you might prefer to inquire from KDS as to price/availability of a
replacement inverter board. Less likely, since it initially lights, the
fluorescent lamp itself is marginal/bad.




QUESTION NO. P41702-5:
HP D7480A monitor with wide screen and no horizontal size adjustment.
On-screen display works and shows that the adjustment is being made but the
picture doesn't move. Checked B+, +5 & +12. All are ok.

HP is notorious for
using the same model # with different chassis, so check if yours has a Tatung
C7B chassis code. If so, dual rectifier D434 (DMV32) is probably leaky,
and should be replaced. Less likely, transistor Q470, or IC401, has gone bad.




QUESTION NO.
P41602-9: Intex TN1473-8 (Jean) monitor FCC AMP JK1470. Vertical frame
collapsed to a thin horizontal line.

In a Wen-brand unit
(same FCC#) with the same fault, U201, D201, R206, R207, and R210 were
defective, so try checking those components in your Intex-brand.




QUESTION NO. P318-3:
How do I set the color balancing on the Samsung 400b, 450b, 550b, 500b, as
well as the Compaq V75 monitors? These monitors do not have internal
adjustments.

All the Samsung
monitors made in the last few years need a "Softjig" to do any
setup. This is a computer interface along with the appropriate software that
allows you access to a factory settings. You can get this from Samsung. Sony
uses a similar setup called "DAS".




QUESTION NO.
P40802-5: Mag DX-17F monitor with R501 removed, I need to know the
original value. I checked and replaced as necessary all the common
stuff for this chassis (including L105).

R501 is a 2.4K ohm
14 W resistor.




QUESTION NO.
P41502-10: Viewsonic G810 monitor will not adjust fully bright.
Osd window ok but screen dull.

There are at least
four versions for G810, but if given no suffix, I will assume this is FCC#
GSS21001 (HV8 chassis). If the OSD is good, then probably this unit
needs re-adjusting, using Viewsonic's alignment software (get this from
Viewsonic). But if you are running this unit on a test bench with a
video splitter, try driving it directly, first, as sometimes these have
brightness problems using a video splitter.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:14 am







QUESTION NO.
P41502-10: Viewsonic G810 monitor will not adjust fully bright.
Osd window ok but screen dull.

There are at least
four versions for G810, but if given no suffix, I will assume this is FCC#
GSS21001 (HV8 chassis). If the OSD is good, then probably this unit
needs re-adjusting, using Viewsonic's alignment software (get this from
Viewsonic). But if you are running this unit on a test bench with a
video splitter, try driving it directly, first, as sometimes these have
brightness problems using a video splitter.

The chassis # is
21VS001. Update on monitor is that after a few minutes of running monitor
screen now goes blank. Osd still operational although slightly out of
focus. Checked heater voltage and it reads just over 6.0v.
Suspect possible problem with hybrid crt driver on neckboard(VP3628-1).
Need pinout for this ic and substitute/replacement if possible.




QUESTION NO.
P41102-2: AppleVision 1710 monitor M2935 sn/ SG5463P565J is failing to
display the red portion of the video. It does include the red gun
output in the default OSD boxed brightness/contrast adjustments so I believe
the problem may be in the CRT video board. The video signal cable has
checked out O.K.

Use apple machine
with monitors & sound control panel or applevision software 1.5.3 or
later which gives you the ability under color tab to recalibrate the
monitor. Apple recommends trying at least 6 times to recover the
board. If not, remove the cover of the video board and resolder the
three transistors but be sure to connect the after thought wires coming up
through the holes or it will not fire up.




QUESTION NO. P40802-4:
Acerview78ie monitor with a horizontal collapsed (top to bottom).

Replace TDA8351
vertical IC and check C368 22nF 2kv cap also.




QUESTION NO.
P41202-3: Samsung MDL. 750s monitor chassis DT17L. Q404 horiz has
house nos. C5802 not available what is real replacement number? D406,
what is replacement number?

In the schematic,
Q404 is KSC5802 (Samsung/Fairchild). This is not really a house number, for
this device is publicly-offered. Possible substitutes might be 2SC5299
or 2SC5387. D406 is ERD07-15 (Fuji Electric); a possible replacement is
a Philips BY228.

Transistor Q404 is
not 2SC5802 but KSC5802 by Samsung. Samsung part number is
0502-001129. It is a common failure part.




QUESTION NO.
P312-9: Sony CPD17SF2 monitor, high voltage comes on for about 30 sec
and then shuts down. Both leds are blinking. HOT and fusible
resistors are OK.

Q510=HV reg o/p
transistor is nearly shorted, about 200 ohms and must be replaced, Sony #
8-729-033-93 located in D board.




QUESTION NO.
P41102-3: NEC Multisync 70/pn 7701 monitor. Three months ago
replaced F101, Q101 burnt, ZD101 shorted, C119 burnt when Q101 blew, C156,
and U101. Now F101 blew and Q101 and ZD101 shorted again.

If Q101 and ZD101
shorted, you should replace U101 once again; also check on the condition of
TH101, the 4-Amp inrush current limiter. TH101 should be roughly 5 ohms
when cold (25°C). These units can get bad solder on the board, so
check/repair solder, and they get bad caps, incl. C107, C117, C121, C122,
C156, etc, so check generally for leaky or open/shorted caps. There is
also a stand-up resistor there, near a diode on a heatsink, that will short
out Q101, if its lead touches the heatsink. If Q101 still blows, try
ringing the SMPS transformer primary.

I found filter C105
across the bridger no good . Replaced it along with Q101, Zd101,and U101.
TH101 read 5.5 ohms, but replaced it anyway.




QUESTION NO.
P41102-9: Proview 986M monitor, FCC IJE986 will power up ok without
signal applied. Once signal cable is connected monitor will shut on and
off rapidly. Now will not power up at all, have checked for the usual
type of failures and shorts but so far no luck.

Check D632, C635,
Q630, Q65A, and R65B (47 ohm). D632, in some units, is a pair of
rectifiers, and D632 may test good when it is not.




QUESTION NO.
P329-5: Apple Multiple Scan M2943 monitor, the customer said it made a
pop, then smoked. It was showing a line up the middle of the
screen. I found R410, R475, C416, and Q418 burned beyond recognition, I
need the values.

R475-68 ohms,
C416-514J mp250v, Q418 K1035. In the two chassis I have, there is no
R410.




QUESTION NO.
P41002-5: ADI LM1764 monitor (Microscan range) FCC BR8LM-1764, the
display has become very unstable, it changes in width / height as brightness
/ contrast are adjusted.

Try checking C851 =
47 uF cap. Replace with a 250 Volt, 105° cap, if possible.




QUESTION NO.
P40902-8: IBM G74 monitor. Photo transistor OP601 PC123 (made by
Sharp) and video driver LM2405T burnt. What is a reasonable substitute
for PC123?

The Sharp PC123
optocoupler resembles an NEC PS2501-1. This NEC device is listed by
Mouser ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and Digikey Corp ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] among others.




QUESTION NO.
P40802-6: Sony GDM-500ps monitor with vertical centering problem.

Check IC007 =
CXA2043Q (Sony p/n 8-752-078-46), it is a known-failure chip. Note,
sometimes DAS alignment is needed, after replacing IC007, so you might first
check IC702 = LA7841L, and its surrounding components, before replacing
IC007. If you do not have DAS, you might send this to a Sony-authorized
shop, for the alignment.




QUESTION NO.
P40502-7: TVM as6s monitor has no image, power supply in
protection. I changed the line driver 2sc5148 for a bu2525af. The
image is now too wide and the adjustment button does not work.

First, check 3 Amp
ultrafast rectifier D406, and transistor Q424, for reverse leakiness or
short. If these are OK, check coil L413 for shorted windings.




QUESTION NO.
P40202-1: Proview PV-850DM monitor, need value of R623, R666, R637 and
R634. All burned beyond recognition.

Proview model
numbers are ambiguous, but if the FCC number is IJEPV-564D, I show R623 as
4.7 ohm (fusible); R668 as 150K; R637 as 10K; and R634 as 2K. In that
circuit, if these resistors were burned, I would suspect a defective flyback
transformer.




QUESTION NO.
P40402-10: Mercury D7032ND monitor. I need a sub for IC109
(5S0965).

The full number for
that IC was KA5S0965, formerly manufactured by Samsung/Fairchild.
Fairchild ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] has replaced it with their newer IC, part
number FS6S0965R, which is currently available.




QUESTION NO.
P40302-8: AOC Spectrum 4Vlr monitor has no +12V on output of regulator,
on Q909 E = 14V, C = 0V output to IC904, B = 0V (If I open J041 = 14V).
Replaced Q909, IC904 and surrounding caps.

I believe Q909 will
not turn on, unless activated by Q910, and Q910 is turned off by the
"suspend" mode pin, of the uProc IC. That is to say, the
uProc has shut down this monitor, by turning off Q910 and Q909, and so Q909
is not the source of the fault.




QUESTION NO.
P327-8: Apple Colorsync M3705 monitor has no H.V. in the EHT
(ZL4). SMPS seemed to be OK and have following voltages on the
secondary windings of the ZP1 (200, 85, 30, 12,6 Vdc). After start-up
there are neither supply has driving pulses on the QL11, QL23, QL6.
MOSFET's QL2 and QL12 have app. 200V on their gate and source leads.
How can I check EHT? I replaced TDA 8172 without solving my problem.

HV will not come up
unless it gets the signal from apple CPU or Soncor unit with adapter.
If you have either of these then the processor on the video board gives the
signal to the MOC2A60-5 opto-isolator which in turn switches on the
bridge. Common faults include RL83, RL59, QL2, QL23 & 22 ohm
resistor close by or RP49 can affect the start up sequence. If these
fail to operate the HV will not come up RP49 is a PTC thermistor that either
burns or goes open, check all solder joints as well and make sure the video
board ground wires are not broken.




QUESTION NO.
P40202-5: NEC Multisync 6FG monitor. The led is green, when I
turn on click, click (about 5 seconds, the Led is blinking) and then the led
is normal. The HOT (C3998) is too hot and then burnt, I guess that the
HOT (C3998 ? Volt, 25 Amp, ? Watt). Can I use C3997 (20A) to change the
C3998? Or can you tell me the equivalent of C3998?

The 2SC3998 should
be readily available, but 2SC5047, 2SC5444, or 2SC5453 might
substitute. I don't recommend using a 20 Amp HOT, to replace a 25 Amp HOT.
If your HOT was too hot, check or replace Mosfet Q5G6, it is probably
bad. Also check capacitors, like C571, C572, and C573.




QUESTION NO.
P40202-8: Iiyama VisionMaster PRO 21 Model MT-9121 monitor with burned
HOT. What is the best replacement?

My notes show the
OEM HOT in MT-9121 to be 2SC5045, and original is always
"best". Since this is a 1600V HOT, substitutes are limited,
but 2SC5451, 2SC5588, 2SC5553, or 2SC4896 might work.




QUESTION NO.
P40102-10: Apple 750AV M2935 monitor. I need values for RP49 RP3, DP17,
IP2 DL23.

The RP49, on the
board I checked, had no markings, and was not a typical resistor, but
appeared to be a custom-made item, in a small white plastic receptacle.
The RP3 = 2.7K ohms; DP17 = 1N5931B (18 Volt zener); IP2 = LM431ACZ (same as
TL431); DL23 = 1N4148 signal diode (if you really meant large transistor
QL23, that was MJW16206).




QUESTION NO.
P40102-5: Proview 772M monitor. I replaced a burned JFET
Q630 (Irf 634) and the monitor works well but it burns again after plugging
the cable for the computer. I change the JFET for a equivalent .
I checked all caps but all is good. I cannot find the IRF 634a .

First, IRF634 is a
Mosfet, not a JFET. Digikey ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is one source for IRF's IRF634
(Fairchild's IRF634A is not much different, electrically). You might be
able to use IRF740 or IRF740A, if you cannot get IRF634. Besides Q630, also
replace the 3-Amp ultrafast diode, D632, and 250-Volt capacitor, C635,
regardless of any testing. If there were any ferrite beads on the legs
of Q630, be sure to retain them.




QUESTION NO.
P40102-9: Gateway 700-069cs monitor FCC BEJCS789 with no display.
HV ok, heater ohms out fine, no OSD, unit powers up fine seems to be running,
but has no illumination. Plug P904 PIN 5 is supposed to be 6.3V, but is
riding at 12V. I tried the easy stuff, soldering, checking for dry
caps, etc.

If the heaters are
getting no voltage, and their supply has no load (6.3V rises to 10-12V),
sounds like a bad connection. First resolder R370 (0.22 ohm) on the CRT
board, regardless of how the solder appears; this is a very common
fault. Also check for bad solder elsewhere on the CRT board and the CRT
pins. The filter cap C922, if not one of the ones you checked, should
also be checked.




QUESTION NO.
P31-9: Gateway EV700a monitor CA-65 chassis made by
LG/Goldstar, P/S hiccups for 5 seconds, then HT is Ok at 160V for 5
seconds, then hiccups for 5 seconds etc. Perhaps there is a short in
the line stage but everything checks out ok.

A common problem is
a bad flyback transformer, 6174Z-1012, but you might also check the voltage
regulator IC's, IC923, IC925, (and IC304 on the video board), as well as
their solder, & check dual diode D704 for any reverse leakiness or
shorts.




QUESTION NO. P329-3:
Acer 7154e monitor, C326 is open circuit, FET Q317 is shorted L304 is
shorted. C335 seems OK, R214 is fine as are Q310, C319, D316,
D317. I replaced the faulty FET Q317and coil L304, but the FET still
blows.

Assuming C326 was
also replaced, that all the other components mentioned are still good/correct
value (a bad C335 or D317 won't always test bad), and the new L304 has not
been damaged by the repeated shorts of Q317, then I would also check C317,
the damper D307, and ring the flyback and horizontal yoke, in case of an
excess load. If it is not this, I would check the components for the
feedback control of the B+ circuit, including IC201 (TDA4858). The flyback
should create a +40V output, using R323, D304 and C306, and this connects via
R220 (68K, 1%), R216 (100K, 1%), plus C237 and C205, to pin 4 of IC201. If
not this, then check components in the gate drive circuit for Q317, coming
from pin 6 of IC201.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:15 am







QUESTION NO.
P328-1: Smile CB6919SL monitor was blowing the main fuse. Q506
(p/n K2828) in the power supply is shorted out. s I cannot find a cross ref #
for it. Is there any thing else I should look at before I replace the
transistor?

If your Mosfet had
shorted to its gate, check/replace components off the gate lead, like
resistors, diodes, and the driver IC itself. You might also ring the
SMPS transformer, in case it had a shorted winding that blew the
Mosfet. The 2SK2828 (Hitachi) is a 700 Volt, 12 Amp, 1.2 ohm, 175 Watt
Mosfet. What makes it hard to cross, is that its gate has built-in zener
protection. If there is already a gate-to-source zener in your Smile's
gate drive circuit, this feature is not really needed, and you might
substitute a plain Mosfet, like STW11NB80 or 2SK2477. Also, besides
2SK2828 itself, gate-protected Mosfets like STW9NC80Z, FS14SM-14A,
FS10SM-18A, or FS10SM-14A, might be possible crosses. Or, you could
install your own gate-to-source zener (18-20 Volts, 0.5 Watt), and use a
plain Mosfet, like the STW11NB80.




QUESTION NO.
P327-6: HP D5458A monitor Chassis Code C5B has a blinking green led
along with the clicking of SR801 (degauss relay). I believe the problem
to be in the power supply. I862 (UC3842B) voltage on pin 7 varies between
10.4-15.1 VDC. The leads on D807 appear discolored but the diode appears
ok.

I don't know your
HP D5458A model, but one of the several chassis installed in the HP D5258A
model is a C5B type, so maybe it is similar. If so, first check the
components for the running supply for the 3842 chip, going to pin 7,
consisting of a winding off the SMPS transformer, then two consecutive sets
of diodes with electrolytic filter caps. If there is a fault here, your 3842
may try to start up, but will not have enough current to stay running.
Also, check the filter cap off D807, for low capacitance, or leakiness, and
check for bad solder on D807 and that cap. D807 & its filter cap
provide the 8V supply, for both the heaters and the 5V regulator for the
micro, so if the 8V supply is poor, the micro could be having voltage
problems when the heaters draw their initial current. If these are OK,
perhaps an overload on one of the secondaries, if severe, might lower all the
other transformer voltages (including the 3842 running supply), to cause the
3842 to start pulsing from undervoltage.




QUESTION NO.
P326-1: HP d2835 monitor FCC a3lcge750 screen is wavy or flickers
continuously every time a full bright window screen is maximized but not at
minimized. The image will remain normal, only the brightness
affected.

In the Samsung 700s
(same FCC number), a bad C517 (a 3.3 uF nonpolarized cap) can cause
flickering that is affected by brightness. C516 might also be checked.




QUESTION NO.
P37-6: AppleVision 750 (M2935) monitor had no operation, repaired dry
joints on FBT & in horizontal circuit. Ran for about 5 minutes then
stopped. Now at power on LED blinks green then goes out. SMPS not
running?

Check MOC2A60-5
solid state relay then QL2 then RL59, RP49. If not, you may need Apple
software to upload data to video processor in gun board.

Check all listed
here previously and also IP1 (TDA4605-3) PWM controller. Replace CP9
also & check the other two electrolytics nearby.




QUESTION NO.
P320-9: DTK M/N DA-456 BA monitor. I need the value for
C441.

220pF 2kV. You'd
better put a 220pF 3kV there.




QUESTION NO.
P322-3: Zenith ZCM-1450-UT monitor, horizontal line in the center of
the screen. I changed vertical output IC LA7838 but no use.

Replace vertical
filter caps as they could be the reason why LA7838 went in the first place
followed by the fuseable low ohms resistor at pin 1 & 8 (VCC pins for
LA7838) leading back to a rectifier diode which leads back to the flyback
x-fmr.




QUESTION NO.
P322-2: Viewsonic Monitor P810, within 2 seconds of power on, it
goes to suspend mode and it's light changes from green to orange. I
checked all horizontal transistors and power circuit, nothing seems
wrong. I looked for dry solder.

Try unplugging any
new USB peripherals that you have and then see if it comes on. It may
be that is has the wrong USB cable on one of the peripherals.




QUESTION NO.
P319-10: HP D2835 monitor FCC A3LCGE750, all the osd controls work
except the pincushion control. The screen is bowed in a lot and when I
go to adjust it, there is a very small movement in the screen. I have
scoped a signal going into Ic 401 pin 3.

C443 3.3uf/50v NP




QUESTION NO.
P318-6: I need the cross reference for transistor Q801 p6n60f of a
Viewmate pwb-1402 monitor.

Possible crosses
include NTE/ECG 2379, or IRFBC40, with insulator; 2SK1118, 2SK1507.




QUESTION NO.
P314-11ViewSonic monitor P817 VCDTS21410-1. Deflection board PBH176-4
replaced with PBH176-6. Horizontal size at low resolutions is too
small. Using software H.SIZE MAIN (DAC F/V2) can be set but can't be
saved using supplied password. H SIZE LIMIT at high resolutions can be saved
without problems. Any idea about hardware changes or data DAC F/V2
saving?

Horiz size at low
resolutions can be saved into "HSize Max Mac480L" window under SIZE
LIMIT menu.




QUESTION NO.
P313-1: Optiquest 4000DX (Acerview 7076) monitor. I need the
value of r378 in the Horizontal circuit. It fried and obliterated the bands.

In the schematic
for Acer 7076i, R378 is shown as 15K ohms.




QUESTION NO.
P313-8: Daewoo monitor 710B chassis. Need value for R939. Too burnt to
read.

The 710B manual
lists R939 as 100K ohms.




QUESTION NO.
P213-5: HP D2835 monitor FCC A3LCGE750, need value of R420 in
horizontal scan circuit.

R420 is a 680 ohm
1/2 watt FP.




QUESTION NO.
P312-6: KD-1700V monitor from KDS. Q404 burned out. I need the
type of this transistor please!

Q404 is 2N7000, a
small N-channel Mosfet. The 2N7000 is made by many manufacturers, including
Philips, General Semiconductor, Fairchild, ON Semiconductor, Vishay, etc.




QUESTION NO. P311-4:
Panasonic Panasync S110 monitor. The HOT 2SC5423 and transistor Q881
2SJ306 were shorted. I changed them and now I have the HV but there's a
single vertical line at the screen, probably the horizontal deflection.
I checked for bad solders or components but everything seems to be
fine. I checked the yoke coil with an ohmmeter and that's fine
too. Could it be the horizontal deflection transformer? With an
ohmmeter, all the pin on the primary have low resistance between them, same for
the secondary.

Q550 is only for
horizontal deflection. Check if its B+ resistor, R890 = 1 ohm, has also
opened up. Aside from the B+ resistor, there should be DC continuity
between the drain of Q881 and the collector of Q550, through the
inductors. If this is OK, check if Q549 and IC580 are good, and
providing drive for Q550. Also check the associated electrolytic caps,
C551, C578, C859, etc.




QUESTION NO.
P218-10: Mag dx700t monitor, the flyback is giving too much voltage to
the CRT connector. Two of the cables that come out of the flyback, one
red and other white, make 1.5 inches of spark, like the other cable that is
connected to the screen. I checked all components from answers in your
database, and they are ok.

If the other
voltages are correct in the Horizontal deflection circuit, replace the
flyback.




QUESTION NO.
P220-8: Dell Ultrascan P780 monitor appears to power up, No green /
amber light. Fuse OK. 120 through the fuse.

Check the
Horizontal Output Transistor. It may be Open, or otherwise failed.




QUESTION NO.
P225-2: Mag DX700T monitor. I need the value of R173, it has
burnt the color off.

The Mag DX700T
model has a couple of different chassis versions, with different FCC numbers,
but I think your chassis version is the one where R173 is 10 ohms.




QUESTION NO.
P129-2: Sun/Sony GDM - 20D10 monitor when cold starting the red color
gun is missing then after 30 seconds the red color gun appears. Also I
need information on boosting or rejuvenating the crt (GDM -20D10) using a
video display tester, Model 490 by BK Precisions. I require information
on how to connect the crt socket pins of the video display tester to the
correct crt pins of the monitor (i.e. G1,G2, Heater etc).

I've restored these CRTs with a Sencore
CR70. I had to do a little homework to get the CRT pinouts
4 G1 Green (at 8 o'clock position next to keyway)
5 Heat
6 Heat
7 G1 Blue
8 K Blue
9 G2
10 K Green
11 G1 Red
12 K Red
13 NC
Heater is 6.3V, Bias is -36V for a M49KZK15X CRT




QUESTION NO.
P129-7: KDS VS-7 monitor FCC EVOKD-1730. Need part numbers for
R463, D408, Q408. There were many caps with the tops blown in the power
supply and around Q408. The unit is making a ticking.

There were a lot of
bad caps, too many to mention but a few in the power supply and the rest in
and around these parts - R463 4.7k , Q408 IRF630 , (D408 IN4148 <-Not sure
about value) also IC801 UC3843AN was bad which kept the unit from firing
up. I still have a problem with what looks like a spiraling rope
vertically on the screen.




QUESTION NO.
P225-9: Two HP monitors D5259A with R451, R452, R443, & R 443
burned too bad for identification. Is there a specific cause?

First, there are
several different chassis that HP has installed in D5259A, from different
manufacturers. You need to provide a FCC# or a chassis code, to help
pinpoint the one you have. IF your chassis code is C7B (Tatung
chassis), my schematic for the Tatung C7B shows R443 = 1K, R451 = 1.5K, R452
= 1K. Also along the same circuit, are C451 (1uF/250V), C323A, C326A,
VR321 (20K), R320 (3.3K), R325A (2.7K), and IC401, so these could be checked
for damage as well. I would also be suspicious that the B+ regulation
circuit and/or the flyback, is bad.




QUESTION NO.
P225-3: Apple Scan 1705 monitor (Goldstar chassis CA-24-6) no
sync. if I remove the memory 93c46, it synchronizes. I need
information on the memory 93c46 to program it.

The Apple
MultipleScan 1705 is a Goldstar chassis, and the Goldstar Eeproms are
programmed while the unit is running, using a special Micom jig. If you
know someone at a nearby LG-authorized shop, inquire if they will program a
new Eeprom chip into this chassis for you. They would need to know if
your Apple 1705 is an M4436 or an M4502 model, to find its listing in their
Eeprom library from LG. Be assured, that Apple itself will NOT be
helpful.


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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:16 am







QUESTION NO.
P225-3: Apple Scan 1705 monitor (Goldstar chassis CA-24-6) no
sync. if I remove the memory 93c46, it synchronizes. I need
information on the memory 93c46 to program it.

The Apple
MultipleScan 1705 is a Goldstar chassis, and the Goldstar Eeproms are
programmed while the unit is running, using a special Micom jig. If you
know someone at a nearby LG-authorized shop, inquire if they will program a
new Eeprom chip into this chassis for you. They would need to know if
your Apple 1705 is an M4436 or an M4502 model, to find its listing in their
Eeprom library from LG. Be assured, that Apple itself will NOT be
helpful.

IC is serial
memory, try National Semiconductor or Microchip (Arizona microchip)
websites. Be warned programming not simple.




QUESTION NO.
P131-4: Peacock PM17P64LR monitor. Need a value of R458. After
replaced Q311-2SC4542, Q313-TIP 47, Q312-2SD669 and R458(replaced with 15
Ohms) monitor runs, but the H-size is too small. After a few minutes
the voltage on R458 (current of the deflection part) increase faster and
faster, then I turn off the monitor before Q311 blows again. During the
current increase the supply voltage also increase. If I reduce the
H-size with the control buttons monitor runs longer until the current start
to increase. I replaced C389 and other capacitors in the deflection
part but without success.

Without having its
FCC number, I cannot be sure, but your description of this Peacock model
sounds like a version of an Acer 76i (FCC# JVP7076I or JVP7176I). The
value of R458 is given as 2.7 ohms, 3 Watts, in the Acer 76i schematic, but
different 76i board versions are seen with values of R458 ranging from 1 ohm
to 3.3 ohm (but not as high as 15 ohm). I would resolder the horizontal
yoke connector, and M605 power supply connector, and also check value on
R239, R243 (0.5 ohm, 1/2 Watt; some versions use 1 ohm), and R456 (150 ohm),
and caps like C341, C343, C390, C391, C395, besides the C389 you mentioned.




QUESTION NO.
P220-2: MarkVision monitor FCC AMPJD144, Q418 (a mosfet k2134) is very
hot and tests short. I replace it with 2SK1117, still very hot.
What is the exact replacement of K2134?

The exact number
for K2134 is 2SK2134 (manufacturer NEC). The 2SK2134 is similar to IRF630.




QUESTION NO.
P220-1: Viewsonic g810 monitor chassis 21vs001 powers up (green light)
but no HV. The switching supply is running and there is drive to the
HOT. Damper diode is good. B+ is good (75vdc)to pin 8 of the
FBT. I cannot find a connection from pin 10 of the FBT to collector of
HOT.

The FBT is driven
by Mosfet Q610; Q550 (bipolar) is the HOT for the deflection yoke. I
believe a diode, D602, isolates the FBT from direct electrical continuity
with Q610.




QUESTION NO.
P26-9: KDS VS-7e monitor, when push any control button, the video
disappeared and can hear relay ticking sound. Then video is back.
CPU is LSC506406B. I doubt CPU bad.

You have a problem
with the EEPROM- small microchip 8pins beside microprocessor. It has to
be replaced with new one or reprogrammed. Common problem for many
models.




QUESTION NO.
P220-6: Acer 76i monitor has a slight jitter or pulling on the outer
edges of the screen. It is very slight at 640x480 but the higher the
resolution and refresh rate, the worse it gets.

You probably have
bad capacitor. Check small cap like 220pf/2kv value connected to HOT
collector. It is common problem with Acer monitors-bad design. This cap
may look like burnt slightly. Better replace that cap with two caps in series
connection. Sorry I do not remember position number of that cap.

I believe it is the
Acer 76ie model (not Acer 76i) which has the problematic ceramic disk cap off
the HOT collector. In the Acer 76i, first check for cracked solder on
the M605 power supply connector and horizontal yoke connector, re-flowing if
needed, and for bad solder generally, and check the ESR on C631 in the power
supply. If this is not the cause, check IC311 = TDA9102C and its
surrounding components; try heat/freeze to test it, or replace the IC.




QUESTION NO.
P219-1: Viewsonic 6E monitor appears completely dead. There is
supply voltage into the power supply with other power supply voltages
present. However, it does not fire up , there is no l.e.d. on switch on
, capacitor C605 stays charged (ouch).

I managed to
locate and repair the fault. There are two 33k 1w resistors in the power
supply circuitry. One of them had gone open circuit.




QUESTION NO.
P213-4: Have a rash of Sony built Silicon Graphics GDM-20D11 monitors
with a wavy herring bone like pattern in the video. It is best viewed
with just a white raster. Problem appears to get better as unit warms
up. Have traced problem to deflection module by swapping out boards.
Suspect leaking caps but can't seem to find the problem.

Despite that swap,
the most common cause of herringbone in the Sony P4 chassis is bad caps on
the A board. If you have many units with this problem, I would check
those caps. Most commonly, bad ESR in the filter cap for the video amp
supply allows noise to enter the supply. In a GDM20D10 chassis here,
that cap is C13, but others include C14, C15, C24, C71, etc.




QUESTION NO.
P124-5: Hewlett Packard D2830A monitor has no power, no light, just a
ticking sound.

Check HOT
transistor - probably is shorted and power supply cannot start.




QUESTION NO.
P212-7: AOC 7G1r monitor, I need a replacement for SUF5402? D921.

This will be a 200
Volt, 3 Amp, ultrafast rectifier. Possible substitutes include SF34 or
UF5402, available from suppliers like Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or
NTE/ECG type 588.




QUESTION NO.
P211-9: EMC Proview 768M Monitor FCC 1JEPV-768. I need values for
R520, R521 and C520 burnt beyond recognition.

R520 = 22 ohms,
R521 = 47K ohms, C520 = 0.01 uF.




QUESTION NO.
P211-10: CTX 1760LR monitor smoked R438, I need the value and any
related components that may be damaged.

R438 = 100 ohm, 5
Watt. Also check Q305, Q412, D410, R353, C308, C423, and check a
47uF/250V electrolytic cap (C135 or sometimes unmarked), at the back, near
L104.




QUESTION NO.
P28-10: HP D2825 monitor, led blinks and no picture. Q317=2sk2161
is burnt.

You should note
that the FCC# of HP D2825 is JVP7154E, indicating that this chassis is like
the Acer 7154e. Check Q310, C319, C326, and replace ceramic disk cap C335
(220 pF/2KV). If C335 is discolored/bad, check if R214 (15K) &
IC201 are defective. Check if coil L304 has shorted/burnt windings, or
if its inductance has dropped much below about 0.6 mH; if yes, replace L304,
or Q317 will die again. Also check if D316 and D317 are leaky in reverse.




QUESTION NO.
P25-8: WEN JD177P3 monitor keeps blowing Q407. It gets hot after
a few seconds and goes belly-up. Repaired supply (few minor
problems). B+ is 220V. Also replaced Q410. Would an IRF740
do as substitute for Q410? Who manufactured this board?

The JD177P3 number
sounds like a chassis from Jean Corp., Ltd. An IRF740 seems reasonable for
Q410, although IRF740A (less capacitance) would be a bit closer to the
original type used. A B+ of 220V sounds too high, so you might check
components off pin 2 of the 3842 chip (off-value resistors, etc) in the power
supply, in case one of these components is causing the secondary voltages to
regulate too high.




QUESTION NO.
P26-6: Digital-pcxbv-pc monitor. I am looking for info and
possible replacement for a HOT made by Motorola and marked "LJH16212".

The FCC# for
Digital PCXBV-PC, A3KM046, crosses to a Philips chassis, and LJH16212 is
Philips part# 4822-130-62701. LJH16212 might be replaced by the similar
MJH16212, so for specifications, refer to the specs in the MJH16212
datasheet, available at
http//repair.vist-v.ru/ds/transistor/bipolar/MJH16212(MJF16212).pdf
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing MJH16212, probably the closest
one. Besides MJH16212, MJW16212 might also be tried, assuming its TO247
case will fit. MJW16212 is the currently-produced version; LJ Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is a possible source.




QUESTION NO.
P117-10: Daewoo 712D monitor. When powered off, vertical blue
line, and then blue spot. I changed the Flyback.

Check G1 & G2
lines to video for broken or bad joints, also check vcc line to flyback for
partially open resistors, check all components on this line.




QUESTION NO.
P118-1: HP D5258A M50 monitor. I need the value of R415 which was
burnt out after replacing R024 (2.2M ohm .5W). The original fault was
dead.

R415 10 ohm 1w.




QUESTION NO.
P25-2: Viewsonic P810 monitor with a power problem. I found IC
S6531 not responding. I need the value and/or an equivalent.

Viewsonic has
several chassis versions for P810, but I will guess that your P810 is FCC# GSS21001,
which is a Panasonic 21HV8SA chassis, in which IC820 is STR-S6531, a Sanken
regulator IC. For this IC, you might substitute a STR-S6531A. Try
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for these IC's. Less likely, your P810 might be
FCC# GSS21010, which is a Panasonic HV10S chassis, in which case, your IC
might instead be IC580 = AN6531.




QUESTION NO.
P21-1: LG StudioWorks 44m monitor FCC BEJCH480. I need values for
R726, R742, C723 which were burnt. I checked the power transistor which
is o.k.

in the schematic,
R726 = 10K, R742 = 33K. C723 is only marked as "105" (I presume, 1
uF). From the locations of these parts, check if the flyback
transformer is defective.




QUESTION NO.
P131-6: Compaq v90 monitor was dead. Repaired power supply,
replaced shorted q831. Starts up but no HV.

Besides Q831, also
check/replace FET Q563 and R866 (2.2 ohm), and test the flyback
transformer. Also, detach the flyback's HV anode lead from the CRT, and
check the resistance from this lead to deck. Any resistance less than
infinite, that appears on the x10K resistance scale of an analog-VOM,
indicates a defective flyback (LZ250A000P, or FEA662), that must be replaced.




QUESTION NO.
P130-2: Dell D1226H monitor FCC A3KM073 has no video. Found Q7543
(MTP5P25) shorted and R3544 burned. I need the value for R3544.

R3544 = 1 ohm, 1/4
Watt, fusible. Also should check Q7532, D6534, and L5526.




QUESTION NO.
P129-1: Gateway monitor EV900. What is the current, voltage, and
recovery time on D315?

D315 is rated at 3
Amps, 200 Volts, and is an ultrafast type (Trr < 50 nanosec).




QUESTION NO.
P125-8: HP2837A monitor FCC A3LCKB722, the FBT (numbered T501 on pcb)
gives ticking noise on startup, green led is lit for 3 seconds, then it
flashes (like shutdown). Both horizontal & vertical deflection
seems working. The Q503 seems ok, tried with substitute. All
voltages are quite ok, only the +13V gives +11V. Maybe something is
loading it. Checked also the IRF740. If I remove drive from the
Q503 (2SC5339?) it does not give the ticking noise. Any ideas what to look
for next and what is the FBT type, could not find any substitute in my
documents? The schematics is quite like Samsung GS450 but there are
little differences. Also checked nearly all diodes.

Since Q503 is the
HOT that runs the FBT, the FBT may be bad. The FBT type is FKI-17A001
in this Samsung chassis. Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] may have this FBT, or
try a Samsung parts distributor. In the UK, you might try PSA Parts
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P1228-4: NEC Multisync A700 monitor, the HOT, FET, Q601 (K2645),
Current Mode Controller, IC621 (KIA3842P), and ZD601 that goes to pin 6 of
IC621 (KIA3842P) are all blown. I need to know the voltage rating for
this Zener.

Since ZD601 is off
pin 6 (output pin) of the 3842, see if it is a gate-protection zener for
Q601, connecting between the gate & source pins of the FET. If yes,
the precise voltage rating will not be very critical. Generally, zener values
from 12V to 20V will work for gate-protection, in circuits that use a 3842 IC
to drive a standard-type FET, like your 2SK2645. Many techs simply use an 18
Volt zener as a universal replacement.




QUESTION NO.
P123-6: Compaq V70 Model 621 monitor. I need value of R632.

R632 = 10 ohm/1
Watt, fusible. Also check/replace Q639, C641, R617.




QUESTION NO.
P123-7: Apple M3705 monitor has a horizontal deflection problem.
I need the value of RL163.

RL163 = 4.7 ohm,
fusible. Also check QL2, QL23, and check for any bad connections on the
horizontal deflection yoke connector.




QUESTION NO.
P122-6: Nokia multigraph 447x monitor I need the value of R205 and a
resistor 1/4W between R194 and C121 which are burned. R120 is burned
too. What would cause this?

Both R195 and R205
are 215 ohm/0.5 Watt. R120 = 100 ohms. R224 = 0.47 ohm/0.5 Watt,
flameproof. Also check FET's T27 and T13, HOT T32, and check inductor
M3 (p/n# FM2525 or FM2565) for shorted or burnt windings. Check the
yoke and CRT board for bad solder, and for any thru-hole rivlets with cracked
solder (both sides). Look on both sides of the board for any tiny SMD
transistors that may be bad.




QUESTION NO.
P118-10: Philips 107S monitor. I need a readily available
equivalent for a mtp6n60 n-channel enhanced power mos transistor. 600v
(vdss) <1.2ohms (rds - on) and 6.8A (id). I checked on the
sgs-thomson site and it is supposedly obsolete.

There are many
substitutes for MTP6N60. IRFBC40 or IRFBC40A (listed by Digikey and Mouser,
among others), 2SK1117, and ECG/NTE 2379 are some of more available ones.

This transistor is
available from Radionics ( [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] ) Herbiton Rd Dublin Ireland or
R.S. components in U.K. part no 441-013 for 2.87 euro + vat a p&p it is
advised to use buz355 800V 6A 220W on a heatsink for testing a suspect
circuit. In a monitor replace any hi voltage caps 1kV and examine
electrolytics for leaks.




QUESTION NO.
P114-7: KDS VS-7 monitor, if the power button is pressed, the monitor
makes a clicking sound and the power LED blinks in sync with the
clicking. The noise seems to be coming from the transformer near the
center of the circuit board. When viewing the board from below, the
board appears to be fried but is relatively isolated. Opposite the
transformer is a heat sink where the board seems to have been fried locally
as well.

Try
checking/replacing Q411, Q408, Q407, and C438, C437, C447, C816. Also
check diodes D404, D405, D409, D410, D411, D412 for any resistive leakiness
in reverse. If any of resistors R901 thru R904 are burnt, the flyback
is bad, and needs replacing.




QUESTION NO.
P116-11: Hewlett Packard 2828A (Acer 7254E) monitor, chassis 7254E, FCC
JVP7254E has no display, just flashing orange LED.

Saw a lot of
previous postings on C335 and area around it in this forum. This only
misguided me and cost me 3 days looking at the wrong area! Shorted Q317
(FET) IRF630M (insulated) replaced with IRFIBC40G (for testing); bad HOT
BU2520DX replaced with BU2520DF. Monitor now powers up with
insufficient horizontal width, and goes into standby mode shortly, more quickly
in VGA mode. All user controls work, but still insufficient horizontal.
Low reading found on C314 (0.00332uF, 1600 KV pps) of 0.01uF. I had a
previous problem with the HOT and FET being blown on an Acer 7211. These
Capacitors are always located on the HIGH VOLTAGE FOIL on HOT's collector
(can't miss it, the foil has extra solder beadings on it). Replaced.
Monitor is now perfect! I also replaced IC 201(TDA4858) but that didn't
improve any. So, don't waste your time & $$$ with that one!

The postings
involving the faulty disk cap C335, refer to the Acer 7154E model (with FCC#
JVP7154E), not the 7254E model, which is different. This sort of ambiguity in
the model numbers which monitor manufacturers assign to their units, is one
of the reasons why it is helpful to include FCC numbers and/or chassis codes
in a posting about a monitor, besides just the model number, and why posting
an abbreviated model description (like "Acer 54e", for example), is
risky (in case there is more than one chassis out there that could be
described thusly), in order to avoid replies about the wrong chassis.




QUESTION NO.
P116-5: EMC aka Proview SA560 (564SA) monitor w/shorted TDA blew R307.
Need the value of R307.

R307 = 10 ohms/ 3
watts.




QUESTION NO.
P116-9: IBM G74 monitor. Opto coupler OP601 PC123 (made by Sharp)
and video driver LM2405T burnt. What is a reasonable substitution for
PC123 opto coupler?

A reasonable
substitute for the Sharp PC123 is the NEC type PS2501, which is carried by
Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and Digikey Corp. ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P114-3: Sony CPD-E500 monitor cannot get the cover off. There are
2 screws on the back and that's it. They were removed and the back half
of the cover lifts up but there is something on the top-front keeping it from
releasing.

A lot of the Sony's
have two locking claws, hiding under the top of the front bezel, a couple
inches in from each side, in addition to the screws. These claws must
be disengaged, by pushing down on the bezel in front of the seam, just before
each claw (or if necessary, by inserting a flat blade at the seam), before
the rear housing will come off.




QUESTION NO.
P111-6: AcerView 78ie monitor. At resolution 1024x768 bottom half
part of monitor is fine top part completely blind and a tiny bright line in
the middle of screen. At low resolution 640x480 or 800X600 no images at
all on the monitor.

Check/replace the
vertical IC, IC201 = TDA8351, and check surrounding components, including the
27 Volt zeners, ZD201 - ZD204, and the values on nearby resistors, not
neglecting fusibles RF208 (1.5K, 2W) and RF209 (1 ohm, 2W). I would
expect about 54V on pin 6 of IC201, from the zener values.


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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:17 am







QUESTION NO.
P17-1: Acerview 78ie FCC JVP7178ie monitor powers up with black screen
and LED is on green. All correct voltages are available from PS.
RF3929 (22 ohm, 3 W) is open. Are C318, C317, C319, C384,C385, C386,
D305, Q304 and Q313 all suspect?

Since the PS
voltages are correct, it is likely there is a defective/shorted component
downstream of RF3929. The most likely culprits on that list are Q313,
D305, C319, and also check Q304 if D305 is bad. Also be sure to check the
flyback transformer.

Follow up: As
I don't have a FBT tester, I decided to replace everything on my original
list except D305 and Q304 (both tested good on DMM). I then installed a
100W light bulb in series with the anode of D305. On power-up, the bulb
glowed at about 1/3 intensity for about 20 seconds and then went out.
Now the bulb no longer lights, D305 has 180V on its cathode and 0V on its
anode (tests good out of circuit), Q313 tests good out of circuit and Q304 is
shorted. Does this confirm a bad FBT?

Check Q321 (IRF
640) and R363 22 ohm 5w (I think) this was probably the original cause but also
replace as a precaution C368 22nF 2kv Z5U capacitor.




QUESTION NO.
P17-1: Acerview 78ie FCC JVP7178ie monitor powers up with black screen
and LED is on green. All correct voltages are available from PS.
RF3929 (22 ohm, 3 W) is open. Are C318, C317, C319, C384,C385, C386,
D305, Q304 and Q313 all suspect?

Since the PS
voltages are correct, it is likely there is a defective/shorted component
downstream of RF3929. The most likely culprits on that list are Q313,
D305, C319, and also check Q304 if D305 is bad. Also be sure to check the
flyback transformer.




QUESTION NO.
P17-6: Gateway EV900 monitor does not work and is missing resistor R573
and variable resistor VR501. Looks like burn marks on circuit board
where they should be. Per other postings, R573 is 68K, 1/8w. What
is the value of VR501? Could the monitor work without these?

VR501 is a 20K ohm
pot. Also, in some OEM versions of this chassis, R573 = 67K; I don't
know if this is significantly different from 68K. These components are
all in the ABL circuit, and are necessary for proper function of the
chassis. Check if D315 in the power supply secondary is open, or has
bad solder; it can cause voltage problems that can ruin the flyback and other
components. The flyback itself should also be checked, in case it is
now damaged and overvoltages the ABL circuit. If so, it needs
replacing. Ringing the fly may not reveal this damage. Gateway
will probably be no help for replacement flybacks; if the fly is FEA658 or
TF2-6V0-002-S0, try Cactus Technology, Nationwide, or Mag Innovision (the OEM
manufacturer).




QUESTION NO.
P1212-9: Packard Bell 1412sl monitor FCC H41CM14011 has normal display
for a second then suddenly shrinks to one vertical line together with a click
sound of a relay. Checked HOT and all the surrounding components in
Horizontal side but seemed to be all good. Checked the Flyback (Sampo
FEA306) and found the ferrite core detached, install to its original position
but still no improvements. If the Flyback is confirmed faulty, where
can I find this one?

Nationwide
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists FEA306, and also suggests TFB4806 as a
substitute. LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is another possibility,
since this chassis is a LiteOn. HR Diemen ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists their
HR46088, as replacing FEA306.




QUESTION NO.
P13-9: AcerView 78ie monitor keeps blowing horizontal deflection
Q314. I need the original part number, it was replaced earlier and I
think my supplier gave me the wrong replacement part. I also need the
value for R713, it was burned.

Q314 = BU2527AF,
and R713 = 3.3K, 1 Watt. You might check the values on R732, R733, and
VR701, as well as the function of IC602 = CNY17-2 (optocoupler) and IC702 =
TL431, in case the 180 Volt rail is regulating too high. I'd also check drive
cap C367 = 1 uF/100V, 105°C for bad ESR, and check RF3958 (1 ohm, 1 Watt,
fusible), and ceramic cap C368.




QUESTION NO.
P13-7: Sony 17SF2 monitor, HOT Q510 failed and had been replaced about
one year ago by expensive Sanyo 2SC3998. Now Q510 dead once again as
well as Q503, D505 and D596. I need characteristics of Zener diode D505
and also any comments about that HOT weakness.

D505 is shown as
RD10ESB, which is a 10 Volt, 0.5 Watt zener, and is across the G & S
leads of P-channel FET Q503. D596 is often 1SS119, which is only rated 30V,
and commonly goes leaky. I'd try ECG519 or 1N4148, instead of 1SS119.
Check for bad ESR/decreased value on C208, C503, and C525, and check film
caps C540, C541, and C592. I'd also check if D501 or D504 have become leaky
in reverse. Note, in this schematic, Q510 is an N-channel FET
(FS10SM-18A); it is location Q507 that is the Sanyo HOT.




QUESTION NO.
P125-4: Octek 1569SE monitor FCC DBL 1569E. Need values for C721,
R712 and R717 in HOT circuit.

A CTX VL500, with
the same FCC# DBL1569E, had C721 = 1 uF/50V, R712 = 33K ohm, and R717 = 12K
ohm. I do not know if all the values will be identical in your Octek
brand, but C721 and R712 are likely to be correct values, since their values
are consistent in a number of CTX models (only the value for R717
varies). However, since these components are damaged when there is a
bad flyback transformer, unless you replace the flyback as well, any
replacement components will again be damaged from overvoltage.




QUESTION NO.
P1218-1: Acer 79g monitor FCC JVP7279G. I need the values of Q313 and
RF3929.

The schematic for
JVP7279G shows Q313 = BU2520DX and RF3929 = 22 ohms, 3 Watt, fusible.




QUESTION NO.
P1220-1: Compaq V90 model 631 monitor FCC BR8SM-994, Hitachi
Tube. Has a black screen, no HV, static is OK, monitor acts like normal
rgd green light, suspend and ST.by. Replaced shorted Hot- Q831, and
pulse IC U505 (uncertain if replaced chip is ok, used). No other
visible burnt components.

Besides the Q831,
also check R866, FET Q563, and check the flyback transformer for any leakage
(less than "infinite" resistance) from the HV anode to deck.




QUESTION NO.
P1220-8: I need the value of R940 in a Compaq monitor CO1021T (710B
chassis).

In the Daewoo 710B
chassis, R940 = 100K ohms. This resistor can burn due to a bad flyback.




QUESTION NO.
P1213-4: Belinea 105570 monitor keeps blowing the horizontal output
transistor. Replacing transistor C5048 (Q301) with BU 2527AF makes the
monitor work for few minutes (display is normal) before display blacks
out.

When replacing any
HOT, there are normally caps in and around the HOT that are open, leaky, or
with bad ESR Also open resistors and/or diodes. Run the set at
around 80 VAC and after 1 min or so turn power off and place finger on the
HOT (the case not the heat sink). If it burns you, you have missed
something.




QUESTION NO.
P1217-1: Compaq V500 monitor, model pe1111 has intermittent
video. I have diagnosed the problem to ic201 (number lsc508418b).
I cannot find a vendor for this part.

This model is made
by Samsung, basic chb5707l and the part number for ic201 is bh0900001a.
It costs about $37.00 in Australia. When it goes, it will give
intermittent video. To prove, use freeze spray.




QUESTION NO.
P1218-3: TVM MD-14IV monitor flickers all the time it from big display
to small display.

Check for cold
solder joints, and bad solder connections in general. If there is a lot
of flux on the board then it is a good indication of a bad solder job.




QUESTION NO.
P1217-2: Princeton ultra 90 monitor dead. Replaced shorted
HOT. No b+ voltage. No obvious resistor shorts. fuses ok.

Princeton monitors
are made by several OEM manufacturers, like KDS, Sampo, ADI, etc., so an FCC
or chassis code number is needed to identify the OEM. Some of these 19"
Princetons are made by ADI, and are similar to ADI's PD-959 model. See
if your unit has an FCC or chassis number that indicates the PD-959
model. If yes, when the HOT Q831 shorts, it generally opens B+ resistor
R866 = 2.2 ohms as well, removing B+ from the HOT. The FET Q563 should also
be checked, as it can be damaged, too. Often, the cause of shorting
Q831 is a bad flyback transformer, which must be replaced, or the HOT will
die again. The flyback may be either model LZ250A000P or FEA662.




QUESTION NO.
P1214-4: Acer 7177is monitor is missing +12v. The voltage
measured at P310 for the 12v is .470v. IC304 pin 9 reads .470v. I need
to know which circuit provides the 12V.

The +12V comes from
+12V regulator IC303. IC303 is powered from the +16V supply, via pass
transistor Q701. Q701 must be energized by Q702, in order to pass
voltage. Q702 can be turned off by a "suspend" signal from
IC701, or if the +24V supply is missing.




QUESTION NO.
P1213-5: Mag monitor FCC IAWU8010 has Q301 shorted, R349 open, R350+351
open. I cannot identify R349 other than the first band. The
bridge seams ok. No other shorts on the input from AC noted. The
TM302 thermistor in the degauss circuit has a part blown off but does not
measure shorted. What are the values of these components and what other
things do I need to check? ie. typical resistance on the output of
Q301.

The schematic for
this Mag shows Q301 as Mosfet FS7SM-16A, rated 800 Volts, 7 Amps, 150 Watts;
a STW8NB80, IRFPE50, or NTE2377 might substitute. R350 & R351 = 0.22
ohm,1 Watt; R349 = 1K, 1/4W. Assuming that you meant TH302, it is
N15SP005 (a 5 ohm, 6 Amp inrush current limiter), equivalent to a
Thermometrics CL-40 device. With these parts damaged, I would also check/replace
ZD301 (15V zener) and IC301 = UC3842AN, check fuse F301, and ring SMPS
transformer T301.




QUESTION NO.
P1212-2: AcerView 79g monitor. I need the value of RF3929 which
was burned. I checked Q313(BU2520DX) and all the parts in this area. I
put (15 Ohm) and same problem.

RF3929 = 22 ohms, 3 Watts, fusible.
Possible reasons for its burning might include excess voltage on the 180V rail; shorts or leakiness
in components Q304, D305, C318, C319; and especially a bad flyback T301. Check the
2KV-rated caps C317, C384, C385, C386, as well, although
probably these would not directly cause the resistor to burn.




QUESTION NO.
P1212-5: Mitsubishi Diamond View (1772E) monitor FCC JVP7276E. I
need the value of r241 (totally blackend) and the reason for its demise.

R241 = 10K
ohms. The usual cause is a bad C327 = 220pF/2KV. This fault can
also damage HOT Q302, Q301, IC201 = TDA4858, ZD210 = 5.1V zener, R326 = 3.9K,
R328 = 4.7K, R329 = 10K, J013 (3 Amp microfuse), and possibly C326 &
C331, so also check all of these.




QUESTION NO.
P1212-7: Dell 1728-LS monitor, built by Samsung. The raster,
color balance, purity, convergence and screen display are all normal. The
brightness and contrast controls are operative, but the maximum brightness is
very low.

See if the screen
voltage or the heater voltage is low. If the heater voltage is bad,
check the solder, and the value, on components going to the heater, including
SMPS transformer T601, D617, R620, C644, J311, J309, CN603, CN105, R165,
etc. Also check the ESR, as well as value, on C644. If these are all
OK, try checking the CRT emissions.




QUESTION NO.
P1210-7: CTX VL950 monitor had a shorted Horiz Output trans which
prevented unit from powering up. Replaced transistor and now have led
& degaussing action but no High Voltage. Checked around for other
part failures but no luck.

Raw B+ (about 200V)
feeds through the FBT primary to Q403, and then its voltage is regulated past
the emitter of Q403, by a coil which is chopped by FET Q338. See if the
coil and Q338 are good, and if the PWM IC, IC303, is providing Q338 with good
drive pulses. If there is no drive, try troubleshooting the UC3843 and
surrounding circuitry, including the HV trimpot feeding back to IC303 from a
flyback winding. Also check for good drive to Q403, from the H/V sync
processor IC, which sometimes goes bad.




QUESTION NO.
P1121-8: Eizo T662 monitor, screen settings are not stored .
Always "default" settings at power on.

I know this problem
from the T562 (17") model, the chassis of T662 (20") should be the
same. Replace the eprom (IC 802), type BR93L66R. It is a SMD
component (Eizo part #08N27578T1) on the video-panel (back of the monitor).


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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:19 am







QUESTION NO.
P1210-6: KDS VS-7i monitor is dead, no leds or noise, no apparent burnt
components, fuse not blown.

Check for broken
solder on the SMPS transformer, and on the flyback.




QUESTION NO.
P1119-4: Looking for correct pinout to a Dell D1028LR monitor with
Philips CM6800 Chassis (FCCA3KM066). The cable is cut at the VGA connector,
pinout for the VGA is no problem, but I need the pinout for the internal
connector.

[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P117-7: I need the pinout of the signal cable of a Dell M990 monitor
FCC A3KM085 (Philips)? The cable is cut at the monitor side. (I know
the connector-pinout, need the pinout of the internal connector.)

[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P111-1: Client was burgled, the intruders stole the PC's but cut the
data cables and left the Gateway EV700 monitors which according to the FCC
search are made by LG. PN 7000920, 700-069ev, FC BEJCS780. We have been
unable to locate new data cables. We have been able to sort out
there/green etc but we are left with several cables and the permuations will
take hours to go through. Does anyone have a source for the cables or a
pinout/color diagram for this model?

[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P1129-3: Samsung CGK5507L SyncMaster 500s monitor has no horizontal
size or pincushion control. Buttons on front panel indicate
functionality, but have no effect on horizontal size adjustment or
side-pincushion and trapezoid adjustment. Q409 and VR401 were
replaced.

Try checking Q407,
D405, D404, D412, for reverse leakiness or short, and L402 for burnt/shorted
turns or rings badly.




QUESTION NO.
P1116-3: Daewoo 710b monitor . I need the values and source of
Q577 and Q935.

In my Daewoo 710B
service manual, Q577 is 2SK2799, a 350 Volt, 10 Amp, 50 Watt, N-channel
FET. A possible substitute might be IRF740A, with insulator. This
service manual shows no Q935, either in the schematic or in the parts list;
perhaps Q935 was added in a later modification.




QUESTION NO.
P118-10: Daewoo or Daytek DT-1728 D monitor, OC-17DB06. I need
the values of R918 and R919 which are burnt out and why burnt out.

R918 10k and R919
is 1.2k. I have never had this problem before, but check Q901, IC901 and
Q906. Also check to see if any of the diodes in the power supply
circuit are shorted, mainly D901.




QUESTION NO.
P1114-4:L Viewsonic 1769gs-2 monitor FCC gss17005 has no
hi-voltage. Fbt, hot, etc seem ok. Replaced lm-2931 & 74hc00
on the aux. board. All ps voltages ok

If the HV builds
and collapses, and everything else is ok, then you may have a shorted transistor
on the CRT socket board. Try desoldering the RGB cathodes at the CRT
socket and see if the HV builds and holds.




QUESTION NO.
P1023-2: Gateway EV900-7000595 monitor. I need the value of R537
which is burned. What could have caused this?

Did you mean R537
or R573? R573 is 68K, 1/8w.




QUESTION NO.
P1029-9: Apple 1710 A/V monitor would tear horizontally after warmed
up. By blowing air across rear of unit from external cooling fan,
problem would go away. Before I was able to track down faulty component
unit went dead. No Power LED no HV.

The problem is on
the CRT socket board.




QUESTION NO.
P115-1: Sun/Sony GDM-20E20 monitor when turned on, the power LED turns
solid green for a few seconds and then goes off ,and immediately after that the
other LED (standby/power saving) turns amber and blinks. This happens
irrespective of whether the vga cable is connected or not.

Start with Q507
(IRF9630), Q508 (C3997), PS501 (pico fuse, open). Sometimes IC420 (CXA1907S)
causes problems but they are usually related to G2, Dim picture etc. While
you're in there, better check soldering around the FBT and also filament
voltage supply caps C677 and C683.




QUESTION NO.
P1114-8: Compaq S500 model PE1112 monitor chassis cmc-518x/522x clicks
the relay when power on and the power led blinks. Found R554 fried,
what is the value and what could be the fault?

R554 is 15k , 10% ,
0.5watt.




QUESTION NO.
P1114-7: Hyundai 7870A monitor takes about 5 min. for the screen to
light up. The screen is dark the HV is Ok and it gets lighter and lighter
until the luminance is almost ok.

Sound like a
Samsung CRT problem. If your CRT is M41KUK36X07 then this is most
likely your problem.




QUESTION NO.
P1017-4: EIZO-monitor F56 with high-voltage breaking down for 1 - 2
seconds than is ok for 5 seconds, then the same problem again. When
high-voltage is breaking down, a "strange component" (it's not a
resistor, but it looks like a 0.25 W-resistor in a transparent tube,
color-rings green-red-white, named SG702) shows sparkling.

"Strange
component" is a spark-gap (SG702). Usually bad news when one of these
light up. Tube is gassy and anode voltage (24 to 27kV) is leaking into
one of the connection on the tube neck protected by the SG.




QUESTION NO.
P1115-5: Acerview 54e monitor shows a green tint.

First try resetting
to factory settings, by pushing both the Select+ and Adjust- buttons
simultaneously. If there is no improvement, try checking the video
board for bad solder/connections, bad electrolytics, or leaky bias
transistors.




QUESTION NO.
P1114-5: Panasonic S50i TX-T5F73 monitor is dead. On main power
supply board, R803 SCK162 is broken.

SCK162 is an
inrush-current limiter, rated for 2 Amps, and initial resistance of 16 ohms
at 25°C. A Keystone Thermometrics' CL170 device should substitute; Mouser
Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists CL170. This monitor may have taken a surge
on the AC power line, or had a short in the primary. I would check main cap
C820, bridge diodes D801-D804, line filter L801/L802, fuses F801, F802, F804,
F805, and FET Q820. If Q820 had shorted, check components off its gate,
including IC820, and ring T801.




QUESTION NO.
P117-10: Optiquest V73 VCDTS21433 monitor is dead, the led stays
amber. All the caps are ok with ESR.

Check Q550, Q881,
T823, and IC841.




QUESTION NO.
P116-4: CTX vl700 monitor is dead. Q313 (HOT) shorted, replaced
by ecg2365 & Q306 (mosfet J306) short & replaced. Dead again,
both are shorted.

Besides replacing
Q313 and Q306, CTX advises upgrading C340 to 47 uF/250V. Also check
ZD303 and R362. If your VL700 (there are multiple versions) has R124 =
82K in the power supply, check that its value is correct, in case this has
caused an overvoltage problem. If this is no help, I would suspect a defective
flyback, FEA667.




QUESTION NO.
P1031-4: Sony CPD200GS monitor. Is it possible to reset when the
firmware appears to be corrupted?

To re-set
adjustments to factory settings, hold the Reset button (second from left) in
for over two seconds. A self-test can also be done, by powering on with
the video cable disconnected, and pushing the right-arrow button for over two
seconds. Four color bars should then appear, to indicate the self-test
has been passed. To change the internal programming, you must use Sony
DAS service software, which is run on a PC with an interface consisting of
adaptor cable, Sony p/n#1-690-391-21; Interface Unit, Sony p/n# A-1500-819-A;
and connector attachment, Sony p/n# 3-702-691-01.




QUESTION NO.
P115-2: Digital FSR871CV monitor, need part no for diode v805.
Already replaced R849 and R869.

V805 is a Philips
BY584. This is a special high-voltage diode (1.8KV, 85mA); do not use a
substitute. A good one will probably read open-circuit on a DMM diode
test, since its forward voltage will be about 3V even with just a 1 mA test
current. MCM Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
are listing BY584.




QUESTION NO.
P115-7: Acer 7176ie monitor has problem with pincushion. Can
align either side perfectly but the screen curves on opposite side. I
replaced Q312, Q313 but this has not made any effect.

There may be a
problem with the Pincushion Balance (PB) adjustment. Try adjusting
this, in factory mode. Power up while holding in the P button, and
release the button after the LED flashes. Enter the OSD, go to the PB
page, and try this adjustment.

That function does
not even out both sides of the full view. If I keep the P button
pressed it will not matter, that will just start the OSD with no different
menus. If I adjust the pincushion to the left the right side gets
curved, if I adjust it to the other side the same thing will happen. When I
start the computer it looks like a D, if I adjust it it goes to the other
side as a opposite D.




QUESTION NO.
P115-10: CTX VL700 monitor. I need to identify Q306, J449, I
believe this to be 2SJ449 a p-channel mosfet. Is this correct and is
there an alternate component similar that can be used?

Yes, that is
2SJ449. An alternative P-FET to 2SJ449, would be 2SJ307.




QUESTION NO.
P104-8: Sony CPD 200-GS monitor. I changed Q507, Q520, IC605
(bad), verified all the components near F/B (ok). What may can cause
Q507 to burn up, when I power up the monitor? Q507 shorts right away upon
powering the monitor.

Is there excess
voltage on the SMPS secondaries, due to bad regulation? If so, check
the value of R628 and R630, off the 180V rail, as well as IC604 and opto
IC603. If the 180V is close, then Q520 should drop the B+ voltage for
the collector of Q507 down to about 74.6 VDC. If this voltage is too high,
check Q520, D516, C575, and the drive circuitry for Q520. In the drive
for Q507 itself, try checking Schottky D502, the values of R517, R518, R522,
the H. drive cap C508, Q511, and T504. Also check tuning cap for the HOT,
C518, (also C521, C522, C579), the damper diode D506, and the solder
connections for the horizontal yoke.




QUESTION NO.
P103-7: Compaq Qvision 172monitor, I cannot adjust the
horizontal and EW amplifier. The image on the screen is not tiled (the
vertical module appears to be good).

If you meant, that
the horizontal width was too small, and the horizontal width and E/W would
not adjust, try checking the small SMD transistor T60, usually marked
"3F". This is a PNP transistor, equivalent to BC857B.




QUESTION NO.
P1016-1: NEC Multisync 70 monitor (model PN 7701), R323 is slightly
burnt and I want to confirm its value.

R 323 is 1K
Brown/Black /Red.




QUESTION NO.
P1030-6: Samtron 70E BASIC CHB7227L monitor FCC A3LCHB770, the raster
width is more than screen width, can be adjusted by front panel digital
control but minimum is more than screen. Originally EHT Xmer, Q506(A733
transistor) & Q504 (IRF730 mosfet) were bad replaced. Present pb is
above mentioned IC501(TL494) POT & resistances are OK & if POT of
width ctrl is varied there is no variation (at PIN 3 of TL494 the voltage is
changing but I think it should stabalize to 1.7(neg. feedback)).

For abnormal
horizontal size, the Samsung CHB7227L Service Manual says to check the output
duty cycle at IC401, Pin 24. If output duty cycle does not vary with
different B+ offset DAC values, check/replace uProc. IC201, and check
components off of IC201, Pins 12 & 16, and IC201, Pin 23. If duty
cycle does vary, then check for a good waveform at T402, Pin 10, on a
scope. If it is good, check components around D432; if bad,
check/replace T402. Beyond the manual's suggestions, also check Q433,
L431, C431, C432, C433, & see if D431 was leaky. Also, IC401 itself
is a known high-failure component.




QUESTION NO. P102-2:
Samsung SyncMaster 753DF Dynaflat monitor, cannot adjust control panel
switch. I replaced IC201 (DM024).

For User Control
Failure, the Syncmaster 753DF Service Manual says to see if the DC voltage
changes at Pin 36 of IC201 when SW201 through SW204 are pushed, and if no
change, to check the button. If the voltage does change, it says to check
IC201.




QUESTION NO.
P1018-2: Samsung SyncMaster 6C CSG 9511 monitor. I need value of
burnt Q504.

My schematic shows
Q504 as a 2N4403, in the circuitry for T504.




QUESTION NO.
P1016-10: NEC Multisync70 P/N PN7701 monitor is dead. The fuse is
open; th101 broke; q101 is burnt w/o markings, also zd101 also burnt. I
need their values.

F101 = 3.15 Amp
fuse, Q101 = Mosfet 2SK2645 (600 Volt, 9 Amp, 50 Watt, N-channel), and ZD101
= 18V Zener. Since ZD101 and Q101 burned, also replace IC101
(UC3842). TH101 is an inrush-current limiter device, rated at 5 ohms
with no load, and 4 Amps max.; a Thermometrics type CL-150 (Mouser cat.#
527-CL150, or Digikey cat.# KC015L-ND) could substitute for those specs.




QUESTION NO.
P1015-1: AST Vision 7N monitor. I need the values of R915 and
R916.

If this AST 7N
model is similar to KDS models KD1710 & KD1711, made by Korea Data
Systems, then the values in the KDS schematic read as R915 = 180K and R916 =
100K.




QUESTION NO.
P927-2: Dell d1025he monitor FCC iey447s. I replaced the hot as
it was shorted. Now on turn on, there are power supply voltages but
nothing on the collector of the hot. I am getting the correct pulses on
the base of it but still no H.T.

See if R411 has
gone open-circuit. If so, before powering up, also check D404 and T404.




QUESTION NO.
P1023-2; Dell D2026T-HS monitor is very dark (only can shows the
OSD). We found a low G2 voltage, the G2 control transistor is ok.
Is there a protection control circuit that shuts it down?

Assuming that your
Dell's FCC number shows that it is a Sony GDM20E03 chassis, the probable
cause is a defective IC, CXA1907S, on the CRT board, Sony part# 8-752-071-56.
If the output voltage from pin 22 of the CXA1907S is too low, going to IC407,
this will cause low G2 voltage. To remove the old IC without lifting PC
traces, it is best to cut off each pin, and remove the pins one at a time.




QUESTION NO.
P1015-2: Philips 4CM4770 monitor intermittently out of sync. In
the deflection circuit found TDA4850 (and TDA4861), TDA2595, HEF4528BP and a
74HCT86N.

Hor. or Vert
sync? If hor, check components around the Hor Osc of TDA4850 and check
components around Vert Osc if Vert sync problem. If there is a pot for
adjusting the Hor hold, then adjusting that might help since it might not be
optimum.




QUESTION NO.
P1016-4: Mag DX1795 monitor. The HOT was blown and the replacement blew
instantly. Flyback rings good, T501 and FET Q506 OK. A casual
check of nearby semiconductors revealed nothing, no visual clues.

Although the
flyback rings good, the capacitor inside might be shorted. There is a
3nF capacitor in the flyback. Firstly with a multimeter connectng one
end of the probe to the anode cap and another to the ground/feedback pin of
the flyback. If you do not know which is the pin then try all. It
should all be open. If low resistance, then you have a bad cap.
Refurbish the FBT or get a new one.




QUESTION NO. P1019-3:
Acer 1555 monitor came in with an S/C line output transistor, type
BU2508DX. I fitted a BU2508DF as the nearest equivalent. It now
has a small picture, width about 50% of normal is the best it can do , but
perfect geometry which is adjustable. The B+ PWM is only delivering 60v
to the Line Stage (should be around 90-100v). The drive to the PWM FET
Q317 is correct, but I replaced the TDA4858 anyway. L304 and D317
replaced too, to no effect. I cannot decide whether the line stage is
drawing too much current (Flyback tranny failure?), or some other component
in the output stage is causing the fault. C335 is an upgraded 3kv cap
ex-factory.

Ring the yoke or
swap a tube/yoke assembly to confirm that it is not the yoke problem.
Narrow horizontal width can be caused by shorted yoke. Since all the
geometry control works fine, I cannot think of anything else to do except the
above.




QUESTION NO.
P1019-9: Dell 828Fi monitor. During bootup sequence, it seems to
loose horizontal sync and controls have no effect. I suspect TDA9109 might
becoming progressively faulty, but I would like confirmation.

TDA9109 is a common
failure in this chassis, and it can give a variety of symptoms, such as
jitter, bad linearity, loss of sync, loss of user settings, etc. Try
some freeze mist on the IC, sometimes that helps diagnose it. If this
IC is replaced, be sure to use the exact same version of TDA9109, as was
originally installed; TDA9109 and TDA9109/S are different chips.


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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:21 am







QUESTION NO.
P926-3: Daewoo 710B Monitor with R939 burning up. I need the
value and why it has gone o/c.

R939 = 100K ohms.
When R939 burns (and/or R935, R940, R947), a faulty flyback transformer is
the usual cause, and needs replacing.




QUESTION NO.
P1017-2: Sony gdm20e01 (Radius 0461) FCC ak8gdm20e01 monitor. I
need the value of R868.

The value of R868
varies, in different versions of the Sony GDM20E01. If R851 = 2.2K,
then R868 is also 2.2K ohm. Some chassis have R851 = 5.6K, and there
R868 = 1K.




QUESTION NO.
P1017-7: Compaq V90 model 631 monitor. Replaced the HOT(BU2520DF)
and FET (k1006) which was shorted and burnt 2.2ohm resistor. It started
to work, now I hear a loud "tick" sound from FBT or nearby
intermittently. At the same time the picture shrink or move a bit and
go back to normal. I tested it for 3 hours, same problem, I also did a
cold start and still same problem.

The flyback (Sampo
FEA662) is probably faulty; it is a common failure in this chassis, and a
faulty FBT can cause those components mentioned, to fail. Also, check
the components off pin# 8 of the FBT, as well, for possible damage.




QUESTION NO.
P1010-9: ctc-146L monitor is dead. Changed HOT, fuse and R106u
4.9ohms. cr118 is ok.

Locate broken
ground connections at the rail that goes around system control IC's U3100 and
U3300. The rail is used as a ground jumper to connect the ground to the
control buttons, solder the rail ground connections. For more info
trywww.videotech.org/rca.htm.




QUESTION NO.
P1015-10: Acerview 7154ei monitor, replaced burned output transistor
q310 and d312, still no power and the power lamp is still blinking. I
checked regulator q602 in the power supply, it is okay. I checked
switching transformer in the power supply and found 80 volts in the primary
and secondary no voltage, also no 5 volts in the regulator and no 12 volts.

Replace disk
capacitor C335, and check R214; if R214 is bad, also suspect IC201 is
bad. Check C319, D316, D317, FET Q317, and coil L304.




QUESTION NO.
P1015-9: Need part number for Q901 in power supply of AOC 4V
monitor.

Q901 is
IRFBC40. This should be available almost everywhere.




QUESTION NO.
P918-10: Daytek DT-1536D monitor is dead. D813 failed short
circuit. IC801, R820, R905 burnt. What are values for these components and
did failure of D813 cause problem?

D813=Z6.2M,ECG
137A, IC801=STK73907 (12 pin Sanken brand sw reg IC), R820=22K ohm,1/4 w,
R905=does not exist, R805=33K ohm,1 w, R804=33K ohm,1 w. Check
Q807=2SC3230,Q802=2SA940,D814=1N4148, solder T403=pin 1 of flyback,R445,and
R444.




QUESTION NO.
P109-8: Gateway ev700 monitor, picture is red, on screen menu prompt
has all colors. Checked red, green and blue crt drive transistors
ok. Green control on crt board has no function.

Found problem with
serial port on computer, all colors there when wire was wiggled, repaired
solder connections on card.




QUESTION NO.
P1011-3: Sampo Alpha Scan 950 monitor, will not light up, just
ticks. Can this be the high voltage power supply? If so where can I
find this part, I've searched everywhere?

If your everywhere
includes the HOT, damper diode, fast rectifier diodes, diodes around the
deflection circuit, no bulging or shorted capacitors, then I suggest that you
check the flyback. I have refurbished many Sampo flybacks before, they
tend to have an open capacitor or shorted coil. To confirm, ring the
flyback. To check the capacitor in the flyback, connect a capacitance
meter with 20nF range and measure the internal flyback capacitor from the
anode cap to the ground/ feedback pin on the flyback. You should get
about 1.5 to 3nF. Much more or much less, you have a problem.




QUESTION NO.
P1012-3: NEC jc 200 2vma-1 monitor. I replaced the
horizontal transistor HPA 150. It works well with the
horizontal york plug off the motherboard. The minute I put it
back it, blows the transistor. Checked for any leaks into the
chassis, it seems to be fine.

On NEC's, when the
HOT blows, the B+ regulator FET generally also is damaged, and if both are
not replaced at the same time, the damaged FET will blow the new HOT, from
excess B+. There's a couple board versions in JC2002VMA-1; usually the
regulator FET is Q5P0 = 2SK758, but may be Q5G6. Also check H. drive cap,
C541 = 100 uF/35V. Be sure your HPA150 has an internal damper, despite
the presence of D561 & D562.




QUESTION NO.
P1012-8: KDS vs-7 monitor FCC evokd-1730. The power supply keeps
cycling power on and off or power led flashes on and off and power supply
makes a clicking noise. I replaced blown hot, it tried to turn on for a
second but still cycles power checked hot and still good.

If any of R901,
R902, R903, R904 are burnt, the flyback is bad and must be replaced.
Also check IC401, if R904 is bad. Check D402, D404, D405, D407, D409,
D410, D411, D412 for leakiness; C438, C468 (under FBT), C816; Q406, Q407,
Q408, Q415, Q416.

I am not familiar
with this model but very familiar with this symptom. Firstly ring the
flyback. If the primary rings well, check if there is about 3nF from
the anode cap to the ground/ feedback pin on the flyback. If less than 1.5nF,
the HV capacitor in the flyback is opened. Check for short in the
capacitor as well since shorted capacitor in the flyback tend to blow up
components like HOT, B+ boost transistor, diode around the deflection circuit
and cause the power to cycle.




QUESTION NO.
P1012-10: Vicom vm615-2 monitor, replaced d14 and fet w931/p4na80
(replaced with irfbc3) shorted. Worked for awhile then fet
shorted. Checked all resistors and diodes and replaced ic tda 4605 in
the power supply.

The (ST)P4NA80 is an 800 Volt, 4 Amp Mosfet,
and your IRFBC replacement was only rated for 600 Volts. Try a FET of the original
voltage. Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists STP4NA80 and STP4NB80 (cat.
no.'s 511-STP4NA80 and 511-STP4NB80), both rated 800V.
These have TO220AB cases (not self-insulated TO220FI cases).




QUESTION NO.
P1011-6: Micron 700FGx monitor HV9 chassis. I need a cross
reference for Q881 (a TO-220 (plastic tab) marked J306 7H3.

J306 is a 250 Volt
P-channel Mosfet; the full number is 2SJ306. 2SJ306 should be available from
suppliers like LJ Enterprises, B&D Enterprises, MCM Electronics,
Nationwide, etc. Possible substitutes include P-FET's 2SJ307, 2SJ449, or
IRFI9634G. Although I can't recommend this, I believe that in the HV9 chassis,
Q881 switches a 170V rail, so, in a pinch, it may be possible to "squeak
by", using a 200 Volt P-FET, such as IRFI9630G, or an IRF9630 with
insulation hardware.




QUESTION NO.
P1010-6: Acerview 76e monitor. Replaced shorted c237 and burned
r239 and r241, now the led comes on then goes out.

Assuming you meant
C327 (not C237) & R329 (not R239), then besides the parts you replaced,
check the microfuses at J013 (3 Amp), F701, F702, F703, F704, FR101; as well
as C304, D308, L304, ZD210 = 5.1V zener, IC201, Q301 = BSS89, Q302, and Q316.




QUESTION NO.
P109-1: Samsung 400b monitor. I need a source or sub for switch
header "KA2S0880". I believe that it is the TDA9109.

The KA2S0880 is a
Power IC (5-pin TO3P case), made by Samsung or Fairchild; it will be mounted
on a heatsink. It is not the same as a TDA9109. There is no
substitute for KA2S0880. In the US, try getting KA2S0880 from LJ
Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P103-10: Dell UltraScan 17TX monitor FCC AK8GDM17SE2T came in with
tilted picture and blurry screen. Adjusted the screen and focus
controls and got focus, however, the words and letters are in the 3 primary
colors, red, green, and blue. Cannot seem to get the (Purity or Convergence?)
adjustment in. The screen tilt was temporarily fixed by disconnecting a
wire on the Yoke board. Screen came in with all yoke and crt
adjustments loosened.

You are going to
need a service manual, to correctly adjust the purity. Try to get the
manual for a Sony GDM-17SE2T, which should be similar, from a Sony
distributor.




QUESTION NO.
P103-8: CTX 1451c monitor when shutting off it decays too slow causing
a burn spot on the phospher in the middle of the screen.

Try checking Q408
(BF423) for leakiness or short.




QUESTION NO.
P102-8: Compaq V75-624T monitor, the power led becomes green and after
a few seconds dies. HOT is OK, output vert. transistor is OK. Is
in PWSP the trouble?

Could have a faulty
flyback transformer.




QUESTION NO.
P102-1: Samsung Sync Master 550s monitor there is power but no display
(no static sparkling). I checked & replaced FBT, CRT Display Unit
and Video PCB Board.

Be sure that there is 6VDC in the filament
hot on crt and move the screen boton on the flyback. Check if 70 or 80
VDC exists on the cathodes of the color transistors. Check the circuit
of ABL it can has a resistor open.




QUESTION NO.
P925-1: Compaq V70, 629 monitor, FCC BR8SM-769(ADI). Replaced
shorted HOT Q813 (2SC4542), transistor failed almost immediately. B+
OK. Horizontal drive pulse OK.

First ring the
flyback. If the primary rings well, check the HV capacitor by
connecting a 20nF range capacitance meter between the anode cap and
grounding/ feedback pin on the FBT. The meter should read 1.5 to 3nF
generally. If lower or shorted, change the FBT.




QUESTION NO.
P925-4: Dell D1728D-LS monitor, FCC A3LCMG737 will not power up,.no
response. Switching power supply appears OK except no 12VDC at one
point on board.

Check if R508 has gone open-circuit.
Depending on the A3LCMG737 board version, it can be either a small-value (1.8, 3.3, etc, ohm)
fusible resistor, or a 1 Amp microfuse, on the 195V
supply. If it is bad, also check if HOT Q502 has shorted, as well.




QUESTION NO.
P828-10: Dell D2026T-HS Ultrascan 20TX Sony vertical is very unstable,
poor pincushion. The front controls will not adjust the vertical width
or position. I am suspecting the circuit around ic 502. I replaced the
vert ic TDA 8172, and all electrolytic caps around it with no effect.

I am more
suspicious of the IC007 (Sony part# 8-752-076-34), on the D board, than of
IC502, for this type of problem; it's a known failure component.




QUESTION NO.
P828-9: Sony CPD-420GS monitor missing Q901 and Q902. Need
part #'s for these and any common failures.

In three similar
Sony models (GDM-400PS, GDM-500PS, CPD-520GS), the Q901 = 2SC1623 and Q902 =
2SA1037K, so probably they are the same types in the CPD-420GS, as
well.

Q901 is a IRFI9634G
(Sony # 8-729-043-63) Q902 is FS7KM-18A (Sony # 8-729-045-22).




QUESTION NO.
P827-2: Compaq 461 monitor FCC IDBR8SM-5514N. I need the part
number for HOT Q809. Also can the damper diode CTPG2F be substituted
with FMGG26?

Q809 is 2sc4747.




QUESTION NO.
P925-9: Water damage from roof leak on a KDS monitor FCC
EVOKD-1730. I need the value of R901, 902, and 904. All have
burned badly. I have not found other parts in this area of the circuit
that are defective. What may have caused these resistors to burn up?
All are 1/10 or 1/8 watt resistors.

R901 = 27K, R902 =
12K, R904 = 12K; use 1/4 Watt. These resistors will burn when the ABL section of the
flyback, KFS61411A, is defective; replacement FBT's are availablefrom KDS.
Since R904 has burned, IC401 may also have been damaged.




QUESTION NO.
P924-8: Digital PCXAV-WZ monitor. I need a source for flyback
CP334P05301. It seems to be a Mitsubishi flyback very rare to found.

Nationwide
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists flyback CP334P05301, but it is an expensive one.




QUESTION NO.
P918-2: Samsung CGC5607L(D)(T) monitor, the label is in Korea, the only
info that makes sense to me is (maybe) the ModelSyncMaster 500p(T) was
initially dead. Replaced D406 (part no CTPG2F) with a FMGG26 which was
shorted. Unit powered up for about 2 minutes, then the image started to
shake and went dead again. Once again D406 was shorted. I found
out that the original diode was rated at 1500V 10A and my replacement was
only a 600V 4A ultra-fast diode.I then replaced the diode with a Philips
BY359-1500 but when I powered up the unit it still remained dead except for a
low pitched ticking sound coming from somewhere around the horizontal
deflection circuit. Did my earlier replacement damage anything else or
worsen the problem?

Unless you forgot
to use insulation hardware on the tab of that BY359, it does seem likely that
the shorting of the FMGG26 has damaged additional components. First
check if Q407 has now also shorted. If that is OK, see if any components
along the B+ circuit for Q407 were damaged by the overload from the shorted
FMGG26. Start with boost FET Q412 and ultrafast rectifier D411; if
these are OK, then start checking components on the circuit providing the 50
Volt supply for Q412.




QUESTION NO.
P918-6: Gateway monitor EV900 made by Mag is dead, no high
voltage. Power supply seems ok but no b+ to collector of horizontal out
transistor. There is 200v on drain of Q107 which supplies the b+. There
is no out put from IC101 NE555 which supplies gate signal to turn Q107
on.

The common cause of
no HV, when the power LED is lit, is bad solder on all the leads of L501,
near the flyback. Resolder all the leads, regardless of appearance.




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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:23 am





QUESTION NO.
P919-7: Dell D1025TM monitor (Sony chassis) with bad HOT, damper diode,
and fet w/protect zener. I can locate the original HOT, and fet
w/protect zener but cannot find the damper diode. The only numbers on the
diode are DLA 8-J. Sony does not support this monitor and Dell has been
unresponsive.

Toshiba makes a
family of rectifiers with the marking "DLA" and a date-code.
Although it is not the damper, I suspect you are referring to D516, a Toshiba
3DL41A, a 3 Amp, 200 Volt, superfast rectifier. The original is Sony part#
8-719-051-97; similar rectifiers include NTE/ECG 588 or Rectron's SF34.




QUESTION NO.
P921-4: Micron 700FGx monitor. Looking for correct value &
voltage on the ceramic capacitor C556, in chassis #HV9.

In the Panasonic
17HV9 chassis, C556 is 470 pF, 2KV.




QUESTION NO.
P913-9: Data General CM1414t monitor has a Panasonic picture
tube. It is too bright and it has retrace lines. I checked the
back board, it checks ok.

Do you have
brightness control? What is the voltage at G1? Normally if the screen
pot on the flyback is not tampered with, excessive brightness could be caused
by shorted or open components (open resistor is quite common) along the
brightness circuit. G1 should be a -ve voltage and becomes increasingly
positive when brightness is increased. If you do not have any
brightness control, it is almost definite that the brightness circuit is
gone. The negative voltage for the brightness circuit is almost exclusively
generated by the flyback. Trace back from the rectifier diode connected
to one of the flyback pin and replace all faulty components.




QUESTION NO. P910-10:
Dell D825tm (UltraScan 800 series) monitor, very dim picture. C653
which filters the line going to the filaments is missing.

Try 2200uF/16V for
C653. This is a common value for filter cap of filament supply.
Filament should be around 6.3V generally.




QUESTION NO.
P921-1: NEC MultiSync P750 (JC-1744UMA-1) monitor, I need to find a
replacement for Q591. It is shorted and causing the power supply to
cycle. The only numbers on the device are "J306" and
"7G2" Of course no help from NEC. Cannot find any info on their
website (used to have parts lists online).

I believe the
number you need is 2sj306 which is a mos p fet 250v, 3a, 25w. A 2sj307
will substitute ok.




QUESTION NO.
P824-7: Mitsubishi DiamondView 2107 monitor, vertical sides
"tremble" intermittently. Problem is not due to computer
configuration or environmental EMI influences.

Check for cracked
solder joints around r345, t304. You may have to remove white glue to
see joints properly.




QUESTION NO.
P911-3: NEC JC 1531-vmr model 4fg monitor has drifting horizontal
sync. Adjusting horizontal hold pots vr501 & 502 will fix sync for
a short time then it fails again. Replaced LA7850 and assoc caps- no
change.

Check IC 74xx86xx
somewhere on the main board close to the cable coming from the crt bd.
This ic takes the horizontal and vertical signals from the computer and feeds
to the required ccts. It can be influential in resolution changes.




QUESTION NO.
P917-4: Dell D1028LR monitor comes on, but goes off when computer is
restarted and refuses to power up again. No green light, yellow light
flickers sometimes.

Replace component
3110. (Resistor - 220K, 1WJ)




QUESTION NO.
P914-4: Compaq P70 model 622 monitor deflection is distorted at bottom
half, space between lines becomes much wider on a band of approx 1
centimeter, and also the picture cannot be adjusted to cover the last
centimeter of the bottom of screen. (Even if trying to adjust picture
height to max). Have another one with the same problem, but at the top
of screen.

Check the vertical
IC TDA8351, check whether sufficient voltage is being provided to pins 3 and
6, and check for cold solder joints around the vertical section.




QUESTION NO.
P914-5: Compaq V70 monitor FCC A3LCGL777, the video is squashed
into the center leaving a vertical bar about 1 inch in width. I checked
for dry joints / obviously burned components, and have found nothing.

Check if the
deflection HOT (BUH1015, MJW16212, or similar) is breaking down under load,
or is arcing to its heatsink. Also check the value on the B+ resistor
(2.2 ohm), and whether the B+ regulator FET (IRF740 or similar) is being
driven by the PWM driver IC (KA3883, or UC3843A, or similar).




QUESTION NO.
P914-7: Sun/Sony GDM20D10 monitor, image is moved to the right of 5
centimeters. It is not possible to regulate with the remote
control.

Check IC103 (Analog
Devices' DAC8840FS), Sony part# 8-759-041-45.




QUESTION NO.
P820-1: Acerview 76C monitor, when one side is concave the other is
convex, the front panel adjustment as a full range but the picture will not
go straight on both sides at the same time. Replaced IC 201 (TDA4858),
Q303 Q310 (IRF 630) Q308, Q307.

Check all power
supply based on the schematics at
http//rv6llh.rsuh.ru/acer/76c-sch0.pdf. Check components around IC202
TDA8351 as failure of this IC is quite common.




QUESTION NO.
P913-10: Royal Monitor FCC HSUTRLX-754 functions fine other than the
Horizontal Width adjustment no longer functions and the picture stretches
beyond the tube. There does not seem to be any obvious opens or shorts
with any of the discrete components in the Horizontal section. Does the
NT68P62-01 Microcontroller develop this problem?

First, check for
reverse leakage (not just total short) in the modulator-diode half of dual rectifier
D410, and in transistor Q411. If neither of these is leaky, then ring
and check inductance of coil L410, check film cap C431 and C439, and
ultrafast diode D418. Only then, go on to the microcontroller.




QUESTION NO.
P912-9: Medion 1772xe (Acer 7377xe) monitor. Values require for
R330 and R356 directly next to DST. Both are burned.

In the Repair
Datasheet and schematic manual for Medion 1772e (Acer 7276e), value for R330=
22ohm 1/2W and R356=47K.




QUESTION NO.
P912-3: I need the values of R717 and C721 on CTX 1565 monitor.

There is a good
site with schematics at http//rv6llh.rsuh.ru/shema.htm This monitor is there
as well.

When those two
components die, the flyback transformer is defective, and also must be replaced.




QUESTION NO. P912-8:
Samtron 55v monitor has no display and no 12V to ic401. Transistor
A1281 (Q608) and cap104 (c110) short . I replaced A733, causing C428
(50v 10uf ) to blow and transistors Q403 and Q404 leak and short and a sound
coming out. It does not start. When I open ic tda9302 Vcc pin6
the monitor starts but has one line and no sound.

First, Korean
transistors are not "2SA" (Japanese) types. Your "A1281"
is KTA1281, rated at 50V, 2 Amps, 1 Watt. A 2SA733 is only rated for
0.1 Amp and 0.25 Watt; a 2SA1382 will be a better choice. But your
replacing Q608 with A733 is probably not the sole cause of your problems. It
sounds like your TDA9302 IC is shorted, as well as those other
components. Also be suspicious of a voltage regulation problem somewhere,
that gives excess voltage on the secondaries.




QUESTION NO.
P912-4: STX CM-451S monitor. Switch mode supply has failed.
Going through startup / shut down sequence. Suspect 2SK2141, cannot
find info on, or replacement equivalent. Transistor getting warm when
power turned on.

I'd expect the fuse
to blow, if 2SK2141 had shorted. 2SK2141 is an N-channel Mosfet, rated
600 Volts, 6 Amps, 35 Watts, TO220F case. Possible substitutes are
IRFIB6N60A, 2SK1118, 2SK1507, IRFBC40A with insulator, & NTE 2379 with
insulator. If the FET is not shorted, try checking for an overload off
secondary diodes D106 through D110.




QUESTION NO.
P911-7: Mag DX1595 monitor FCC Iawdx15fg . The Horizontal/Vertical IC
TDA9103 has to be replaced because of arcing damage. In a number of
previous answers reference is made to the STV7778S (I have a PDFfor this) .
Is this IC pin and function compatible to TDA9103(PDF now removed by ST
Microelectronics)?

To find out if a
STV7778 can substitute for TDA9103, look at your board, and check whether
pins 6 through 9 of the TDA9103 are being used. If not, then you can
use STV7778 to replace TDA9103. The difference between STV7778 and TDA9103,
is that pins 6-9 are no-connection in STV7778, but in TDA9103, these pins
MIGHT be used for switching in different S-caps. However, many monitors
that have TDA9103 do not use that function of the IC, anyway, and in those
chassis, the STV7778 will substitute for TDA9103. Also, whenever a
STV7778 was the original IC, a TDA9103 can generally replace it.




QUESTION NO.
P97-5: Mag 1795 monitor. No HV, all voltages from power supply
are OK(+42V exists), HV transistor OK.

Check if the 12V
supply to pin 18 of IC701 (TDA9103) is low; this IC often shorts, causing
loss of HV, and must be replaced.




QUESTION NO.
P821-8: Gateway EV-700 monitor, no contrast, bright and contrast at max
, picture very dim.

Check for dried up
caps in the filament supply. Also check the following:
1. Filament voltage. Is it around 5 to 6.3V DC? Measure at CRT board.
2. By turning up the screen pot on the flyback transformer, image improve?
3. Probe the voltage at G1. Change the brightness control G1 change as well?
If answer to (1,2,3) is
(no,yes,yes) - Repair the filament voltage circuit. (yes,yes,no) -
Repair the brightness circuit. It has gone too negative. Can you hear
the static crackle when monitor is first turned on? If yes HV most probably
sufficient. Check B+ is sufficient and measure anode with HV probe if you
have one and adjust if necessary since screen voltage is dependent on anode
HV. After you have repaired the monitor, tune the screen voltage by holding
the brightness control at half way and using a Nokia monitor test software
(available on the net) to adjust the required brightness via the screen pot.




QUESTION NO.
P87-1: LG Studioworks 44i monitor. R843 burned, I need value for
it.

Check the flyback, R843 12K 1/4W, C787
1uF/50V. Also check all components all the way to the ABL pot.
Check the HOT and the components around it as well. If HOT is OK then
most probably the rest of the components are OK as well.




QUESTION NO.
P810-10: Acer/ Aspire 77s monitor, the B+ goes high on, arcs so bad at
the crt board, I cannot get any readings.

If all the surge
protectors on the CRT board light up along with buzzing from the CRT neck,
the tube is gassy and when the monitor is turned on the neck of the tube
glows purple in color, you may need to get a replacement tube.




QUESTION NO.
P831-7: HP M90 Monitor. The pins in the DB15 connector are
bent. Where can I find a replacement cable?

If just bent - Use
a long-nose plier to bend it back. Take your time and do this
carefully. If broken while bending - Cut the cable a few cm away from
the molded plug. Strip the cable to expose all the individual
strands. Measure the continuity of each strand to the pins or stub. You
will have a matrix of strand-pin. Purchase a DB15 plug and solder exactly
following the matrix that you have just drawn up.




QUESTION NO.
P815-6: LG Studioworks 76i monitor shuts off after 2 minutes. If
unplugged then plugged back in, it will work for about 30 seconds.
After doing this about 5 times, the monitor stays on. I checked degauss
circuit and see no problem, even disconnected the degauss coil.

I repaired a
similar problem on a CTX monitor which I had to turn on and off a few times
to get it going and if I have signal going into the monitor when turning it
on, it becomes very difficult to turn on. I had to disconnect the vga signal,
try to turn on the monitor (hear static) and then plug the signal in. If your
problem is similar to what I have described, check the HOT driver circuit.
especially the resistor/s in series with the HOT driver transformer. The
voltage feeding the driver transformer should only be around 24V generally.
If it is too high (say around 85V, this was what happened to my CTX and the
driver transformer and resistor got fried) then there is something wrong with
the power supply side. I mod the driver circuit for my CTX monitor and
use a driver transformer from a Wyse terminal and use the 24V supply from the
vertical deflection circuit to drive the HOT. Unfortunately the monitor runs
hot. If you have to do a similar mod, pay attention to the phase of the
driver transformer.




QUESTION NO.
P97-8: Acer 1768i monitor FCC JVP7176IE. shifts horizontally and folds
over (right side of image on left edge of CRT) for resolutions above 640 X
480. OSD works fine and image is clear. Centering pot not
effective but components around it are all OK. When use air gun to blow
on L307, the image will shift back to the left for a short duration. Cooling
L307 seems to solve the problem. I have not changed L307 simply because
Acer here in my country will not sell me the parts. If someone can confirm
that L307 is a likely cause of the problem that I am facing then I can get
the coil rewound.

The model no.
written on the label on the rear of the cover is 1768i but is really a
7176IE. While waiting for the answer I have managed to solve the
problem (I am using the monitor to write this answer). Do not know why
cooling L307 had the effect of shifting the image back to position but the
cause was really C320, 100pF 2 KV cap. Since then also checked all the usual
capacitors relating to this model i.e., C3950, C3951, C3952, C307, C353. A little
more information for you guys - I also replaced the IC304 TDA4858 but the
symptom remained. However, before I changed the cap (didn't know it was the
cap then), I modified the circuit to pin#1 of IC304. I soldered a 68K
1/2W resistor in parallel with R395 27K increasing the voltage fed back to
pin#1 of IC304. This pin is the HFLB (Horizontal Flyback). This mod actually
solved the problem as well. If you have the circuit, I got mine
from([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] you will see why I eventually changed
C320. C320 dropped too much voltage and hence the amount that reached pin#1
of IC304 dropped as well.

First replace disk
cap C320 (either 100 or 120 pF, at 2KV), because it can also cause a phase
shift problem at higher scan rates (and cooling the L307 area may correct
it). Also check for reverse leakage in D308 = FES8JT, and for high ESR on
C307, C353, C3950/3951/3952. Often when L307 is truly bad, it has shorted
turns or rings badly. If you should need to rewind L307, it is a 20 mH coil.

Check for a bad
soldering joint on L307 (caused by the high temperature of the coil?).
I soldered a 100k 1/4W resistor in parallel to R395 27k effectively making it
22k just for luck.




QUESTION NO.
P96-7: Samsung 4bni monitor. What is the horizontal frequency and
vertical frequency?

If your basic model is a Samsung CKA4227,
the horizontal scan range is 30 to 55 KHz, and the vertical scan range is 50
to 120 Hz; maximum resolution is 1024 by 768.




QUESTION NO.
P96-10: Viewsonic 1562ES-2 monitor FCC GSS15002. I need the value
and part number of Q306.

The schematic for
Viewsonic 1562ES-2 shows horizontal driver transistor Q306 as a Sanyo
2SD600K, and horizontal output transistor Q307 as a Philips BU2520DF.




QUESTION NO.
P95-4: Apple M1823 monitor is bright green during boot but will return
to normal after about 20 minutes. Occasionally flickers to green during
use. Is green after wake up from sleep? Checked cabling, they are
ok.

This fault can be
caused by bad solder on small SMD resistors on the CRT board, that need
reflowing or replacing. To access them properly, you generally first
need to remove the three IC's with staggered leads, that are obscuring
them. For your 'green' problem, I would first check the SMD resistor
(2.7K) off of pin 5 of IC010, then check others.




QUESTION NO.
P95-10: Unbranded model 1768i monitor FCC JVP7176IE. I need the
value of C3950, C3951, C3952, IC303.

From the FCC#, it should be like an Acer
7176ie, where C3950, C3951, and C3952 are all 2.2 uF, 450V, 105°C
electrolytic capacitors, and IC303 = LM7812, a 12V regulator IC.




QUESTION NO.
P822-2: CTX 1565GM monitor. I need the value of Q413 (K890),
R316, R458 and ZD402 (all burned).

The CTX 1562 has a
transistor in the HV section numbered Q410 which is listed in the parts list
as IRF630/890, so I suspect the IRF630 is it. Nearby components in that
same circuit are a 15V 1/2w zener diode, a 2.2 ohm 2w resistor,and a 4.7k
1/4w resistor going to the gate.




QUESTION NO.
P829-10: Proview PV-1768P monitor, only ticking sound. Found dead
Q601, replaced with BU4522, failed after a few seconds. C603 is o.k.

Check b+ fet &
caps.




QUESTION NO.
P830-4: "Tiny" monitor with a LG CA-74 chassis in it (I need
the Goldstar model number in order to order the service manual). The problem
is that the HT rises to 155v-160v then dies back slowly. It then stays
in a safety mode unless it is disconnected from the mains and reconnected
again, it then repeats the above. There is no sign of EHT or output volts
from the LopTx's secondary (no line drive ?????). Is this HT (B+)
correct, it seems to be on the high side to me, pointing a finger at the
SMPS. Also if the LopTr (HOT) is disconnected and a dummy load is used
(or not used), the results are the same.

Being a 19"
display, the LG Studioworks 995E (Model CB995CE, FCC# BEJCB995C) is not very
'tiny', but the FCC website does show this model as being a CA-74 chassis.




QUESTION NO.
P830-3: HP A2094 monitor, replaced Horiz. output, and one FET, still no
horizontal. No B+ on output transistor and component PS301 is reading open,
component is stamped soc1000. Is this a fusable link?

Yes, SOC1000 is
fusible link, rated for 1000 mA (1 Amp), from Sony, who is also the
manufacturer of the HP A2094 chassis. A fast-acting 1 Amp picofuse can substitute.




QUESTION NO.
P829-7: Mitsubishi FFF8705SKTKL monitor, loss of horizontal sync.

The Mitsubishi
Diamondscan 17HX model can lose horizontal sync if the H. freq. data, stored
in memory, gets corrupted. To adjust this data, you must enter factory
mode, and a service manual is advised, as the procedure runs several pages in
the manual. Try getting a service manual from a place like
Electronicsrepair.net ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or see if
your regional tech support will Fax you the relevant manual pages.




QUESTION NO.
P828-7: Sampo Alpha/Scan SV KM-400A monitor. After a few minutes
of power on, the monitor will be out of focus. Adjusting the focus knob at
the flyback regain the good focus condition, but after a few minutes it will
be out of focus again.

Drifting focus like
this is usually caused by a defective focus block on the flyback.




QUESTION NO.
P827-5: CTX VL710ST monitor FCC DBL1795SLU has a short circuit HOT
(Q309) and also short circuit Q308. R393 is burnt beyond
recognition. I need the value. Also, are there any other
components we should check out before powering up?

In the schematic,
R393 = 10 ohms, 2 Watts. Also check other components in the Q308
circuit, L305 = 5 mH, C334 = 47uF/250V, D302 = BYV26C, and ZD303 = 12V.




QUESTION NO.
P824-10: Sony cpd 220vs monitor, the high voltage is ok for few
seconds, orange light comes on and the voltage drops to zero. No shorts
found in the power supply or in the high voltage. I replaced the
flyback, same problem.

These have a flimsy
main board. Check carefully for any cracks in the board, especially
around the front support area.




QUESTION NO.
P824-4: Gateway 500-069cs monitor operation from 220v mains. The
power diodes lights up when switched on but the screen remains off. The
relays and other sounds can be heard but the screen remains off with no
static at all.

First, check for a
broken PCB trace at the intersection of J165, R723, & the back corner of
the FBT shield; if broken, jumper the break and resolder the shield, etc.
into place. If there is no PCB break, and if your chassis is the TCO-95
version, with the two-section FBT, that FBT is a very high-failure component
for giving no HV (no static).




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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:25 am







QUESTION NO.
P823-9: IBM 7095-593 monitor with a pincushion problem. I
replaced the 47 Ufd cap near the flyback and also the vertical IC.

First check
C539. If that is not the cause, try checking IC501 (either STV7778 or
TDA9103).




QUESTION NO.
P821-2: Axion CL1766 monitor. I need a source or sub for flyback
transformer AT2097/02B - E 17865 - 31121TY - 99-40-6055-0007 -
Phillips.

Nationwide
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing flyback AT2097-02B, on-line.




QUESTION NO.
P821-3: Philips 17A, CM3800 monitor FCC A3KM053. Found same problem in
archive but cannot find suggested resistor (R573) as locations have
four-digit designators. Monitor powers on, degauss etc., syncs to PC OK,
initial static crackle and HT present, normal low buzzing sound (quiet) - but
no raster or video. Cathode glows as expected. Cannot determine if FBT is
faulty or perhaps in some DPMS mode?

The archived answer
looks like a typo, for my notes show the 1 ohm resistor near the yoke
connector to be resistor 3570 (not 573). A lot of these units do get
FBT problems.




QUESTION NO. P726-9:
Goldstar Studioworks 74m monitor tripping on cold startup for approx. 30 sec.
eventually starts up. Replaced PSU caps but did not help.

This is a very
simple fault of [smps] type. Change all power resistance above 50kohm & 2nd s.w
VR'S.




QUESTION NO.
P87-7: LG Studioworks 7D (CA-38) monitor has no display, green LED
on. SMPS is ok, HOT Collector 40v Dc, no G2 &G1 voltage, (Flyback)
part no 6174Z-2002A.

This is a very
common fault in LG monitors. Replace horizontal out to bu2508df &
2nd and flyback.




QUESTION NO.
P817-5: Acer 7276c monitor, I need the value of R409 which is
burned.

R409 = 10 ohm, 1
Watt, fusible.

Go to
http//schema99.d2.cz/monitory.htm for free downloadable schematics.




QUESTION NO.
P817-1: Compaq QVision 172 Model 454 monitor. I need the value of
R120, and the part for the SOT23 transistor near R191. I see by another
question ( NO. P114-3) that the surface mount transistor might be a 3F ie
BC857B. I also have smoked R195 & R205 (values 215 ohm 0.5
Watt). Any tips for the common culprit for these failures?

R120 = 100 ohms,
and near R191, there is an SMD transistor that is a 3F = BC857B. Also
check R224 (0.47), C121 (0.01uF), D28 (BAV21), P-FET's T13 & T27, HOT
T32, and especially check coil M3 for shorted/burnt windings.




QUESTION NO.
P816-9: Gateway EV900-7000595 monitor. I need the value of R573
which is burned. What could have caused this?

R573 = 68K
ohm.. First, check if D315 (HER303) is bad. If not bad, or if
replacing a bad D315 does not prevent further damage, then probably the
flyback transformer is bad.




QUESTION NO.
P815-2: AcerView 76ie monitor keeps blowing the horizontal output
transistor. Replacing transistor C5048 with BU 2527AF makes the monitor
works for few minutes (display is normal) before display's black out.
Transistor replaced is not hot when touch right after it becomes defective.

Check or replace
disk cap C320 = 100pF/2KV (might be 120 pF), off the HOT collector. It
is better to replace C320 with a 3KV-rated disk cap. Also replace C307
= 1 uF/50V, check the ESR on C353, C304, C3950, C3951, & C3952, and check
FET Q303 for leakiness.




QUESTION NO.
P810-1: ADI PD-959 monitor. Replaced failed LOPT , BU2520DF drive
transistor & 2 ohm resistor. Powered up monitor, transistor &
resistor taken out again. Found an earlier reference to same problem,
also mentions Q567, a K1006. However, on the PD-959 model I have Q567
is not a K1006. What is the ident of Q567? SMPS is OK and LOPT
O/P is ok.

I believe it should
be Q563 (and not Q567). Q563 is the 2SK1006 that is associated with
blowing the HOT and B+ resistor, when that Mosfet becomes leaky.




QUESTION NO.
P82-9: LG studioworks cb775bn monitor FCC bejcb775b with poor
focus. There is some adjustment using the focus block on the flyback,
but video is still not crisp.

This monitor is
prone to have CRT problems concerning the focus. We replaced a few
under warranty. You can get the CRT from LG but it is cheaper to
replace the whole monitor.




QUESTION NO.
P82-6: Mitsubishi DiamondView 1772e monitor, I need to know what c326
and r329 are. They burnt out.

C326 = 270 pF/500V,
and R329 = 10K ohms.




QUESTION NO.
P82-1: ADI VD-484 monitor. Power LED blinks periodically when turned on
with no change when VGA cable is connected. Traced to possible short in
power switching transformer; Numbers are LT249A 002A (then on next line down)
AXIS 9715, I need a source.

Try contacting ADI
directly ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] 1-800-228-0530).




QUESTION NO.
P81-7: Sony GDM-500ps monitor when turned on high voltage comes on for
a couple of seconds then goes into sleep mode. I have six of them in my
shop.

These units are in
shut-down mode. Best get the Sony manual, for troubleshooting codes,
schematics, etc., Sony p/n# 9-978-594-03, from a Sony distributor.




QUESTION NO.
P731-7: Compaq P110 model 630 monitor. I replaced the cxa2043q on
a P110 but now when I press the ON-SCREEN display button, the display symbol
appears on the left down corner but that is all.

If that was the SMD
IC at location 007, then Sony DAS (digital alignment) will need to be
run. If you do not have that software and apparatus, find a shop with
this equipment, and software for the Sony GDM500 model.




QUESTION NO.
P727-8: Is there a substitute for Samsung (sec) ka2141, a video
preamplifier for color monitors used in Samtron 4bni models?

I know of no
substitute for KA2141. If the problem is no video, first be sure the IC
is not being shut off by inputs at pins 9 (contrast input), 10 (clamp gate
input), 11 (blank gate input), or 20 (brightness control), and that Vcc is
present at pins 5 & 16. If the IC is bad, after all, then try
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for replacement parts of this chassis.




QUESTION NO.
P726-6: Smile kfc ca6736sl monitor. I need the value of
R111.

R111 = 10 ohms.




QUESTION NO.
P725-6: ASTvision 7L monitor has a red screen with red back
traces.

There is more than
one chassis for AST 7L, check for an FCC number. If this 7L is the
Capetronics chassis, check the LM1207 video preamp IC. On the Samsung
chassis, first check IC105 (hybrid IC, MV17LO). If that one is not the
cause, check IC102 (LM2427), and check for a short to the red gun in the CRT.




QUESTION NO.
P724-8: Acer 7156 (acerview 56L) monitor, chopper fet Q604 and chopper
ic both went s/c with resistors in psu going o/c, this was due to main
smoothing capacitor dropping in value to 1uf . I need the value of R622
which is badly burnt.

R622 = 20K ohms.




QUESTION NO.
P723-6: Mag DJ800 monitor sometimes starts and picture comes, but there
is some "noise" on the picture and power supply is noisy. If
I cut the track from T101 transformer it starts without picture and then if I
connect tracks picture comes always. It seems that something takes current
too much and power supply shutdowns.

This monitor is
prone to flyback problems. Replace flyback by TF26V0003S0 available
from MAG Innovision, also resolder L105 and T501.




QUESTION NO.
P720-10: Hewlett Packard d5259a monitor, OEM Tatung c7b. I need
the values of D802 and R430.

The Tatung C7B
schematic shows D802 is 1NU41, which is a 1000V, 1 Amp ultrafast diode (NTE
575 should be similar), and R430 is 15 ohm, 1 Watt.




QUESTION NO.
P717-4: KTX Topscan CAE-364SG monitor originally was intermittently
blue. After checking for dry solder joints the green electron gun was
working but the red was still not working, unless the monitor was on for
around 30min, then it would return to normal operation.

Check L203 and the
old conductive glue on the crt board.




QUESTION NO.
P719-7: Acer 7156S 411 monitor after about 15 minutes of warm up, the
focus has gone high, text is unreadable. If I adjust the focus, it will
work perfectly again. I checked the horizontal circuit and changed all
the leaking elco's but this does not help.

With your
description, change the fbt.




QUESTION NO.
P720-4: AST 4N monitor FCC CSYSC-428PT during the CPU boot-up the
display is horizontally shifted (image appears side by side). When it
goes into the Windows mode there is horizontal tearing (image moves
diagonally across the screen without stopping). I checked the cable,
adjusted VR403 (H-Hold control) and changed the refresh rate of the display
card but no change. I also replaced IC101(LM1203N) and IC401(TDA4850)
but still no change.

Look for an ic
74xx86 and change it with exactly the same type. It is associated with
the horiz and vert signals coming in from the video card from the
computer.

On Compaq's with
that same FCC#, this is often caused by bad solder on IC202, a 7805 IC in the
middle of the board, so check the components in that circuit.




QUESTION NO.
P719-10: KDS VS-7/EVOKD-1730 monitor suffering from blurry display
problems. I see three trim pots on the main board, but the manufacturer was
not kind enough to mark their function on the board. The pots are marked as
VR401, VR801, & VR902. Does anyone know if any of these might be a focus,
or sharpness adjustment?

Those trimpots are
not for focus. It is typically the case that the controls for focus are
on the FBT itself. In this chassis, I believe that the FBT has controls
for both the horizontal and vertical focus. If those controls cannot
improve the focus sufficiently, check out the CRT with a Sencore analyzer.




QUESTION NO.
P717-1: HP D2818A monitor after three to four minutes warm up, the
display becomes reddish and the horizontal line (raster line) comes out.

Check out hybrid IC, IC105, on the CRT board
(might try heat gun or freeze mist), as well as checking for cracked solder
on the pins.




QUESTION NO. P716-10:
I need a supplier for oem Princeton parts such as By329-1500,SSS7N60A and
2SC5386 for Princeton Ultra 72e.

Nationwide
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing all those components. Note, 2SC5386 is a
Toshiba transistor. But if yours is marked C5386, and made by Samsung (SEC),
rather than Toshiba, then the correct number is KSC5386, which is a different
device.




QUESTION NO.
P713-8: Goldstar Studioworks 45i monitor FCC bejcs486 Chassis CA-51 had
no video. High voltage and raster O.K. I found that the video amp
IC301 on the CRT board had no VCC applied to it. IC302 supplies VCC to
IC301. I jumped out IC302 with a resistor to verify IC302 defective,
video came back, good. I cannot Identify IC302 correctly or find a
supplier for it. Markings are KIA76L, it has three pins, it looks like
a transistor, and the case is square.

Your package
description sounds like a voltage regulator IC from Korea Electric
Corp. If so, that part number is incomplete, and probably why it could
not be found. I suspect it is actually KIA78L (not 76L), and underneath
the KIA will be a suffix for the voltage (such as 08.... for 8 VDC
output). The datasheet for the entire KIA78L series is found at [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
These regulators have circuits that will shut them down if either power (0.8
Watt) or current (0.15 Amp) maximums are exceeded, so first be sure your
device is not in shutdown. Also, their pinout (Out, Gnd, In) is backwards
from the usual for 78L regulators. If you cannot figure out the output
voltage for your IC302, it should match the Vcc for the IC301. For example,
the datasheet for MC13280/81/82 shows their Vcc is 8VDC, and so IC301 would
be KIA78L08. A Zetex ZSR800 might sub a KIA78L08, but most 78Lxx
devices are only rated for 100 mA, so a 78Mxx device might be a better sub
than other 78Lxx.




QUESTION NO.
P712-10: TTX TTX-5700 monitor FCC EVOKD-1700V; need to know the values
of R833, R829, and ZD803 in power supply.

In a Princeton
brand with the same FCC#, R833 = 560 ohm, R829 = 220 ohm, and ZD803 = 12 Volt
zener.




QUESTION NO.
P79-1: Hyundai HT-5870C monitor. Is there a factory service mode
for color adjustments? We have a lot of these units to service which
have been converted to Touchscreen and it is worth replacing the CRT but we
cannot adjust the colors due to lack of analog controls.

This worked on some Hyundai 7870A
Touchscreens; perhaps the 5870's are similar. On the side of the main board, there was a connector
for digital alignment. One pin on that connector, 'MF', when shorted to
ground, permitted the chassis to enter service mode.




QUESTION NO.
P79-5: Dell d825ht monitor has vertical foldover on the bottom portion
of the screen. I replaced the vertical output with no luck.

Is there a solid
-10 VDC on pin 4 of the vertical IC? If not, try checking components on
this line, such as C401, C403, D653, C653, and L653. Also, pin 2 should be
+16 VDC.




QUESTION NO.
P79-7: Smile CA6736DL monitor FCC GBVCA6736DS. I need a source or
sub for flyback transformer FEA 527, Samp 9740 ; E1596 58 ; 15-EO24-0419 ;
SE7A 02D4 FM 1057.

Try Nationwide
Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for flyback FEA527.




QUESTION NO.
P75-9: Viewsonic 17g monitor FCC acj93312116. I need the part
number of d510. It is a smd and has M1U on it. Can I use two decrete diodes
and, if so, what can be used?

Panasonic SMD
diodes marked "M1U" are series-connected dual Schottky's, rated at
30 Volts and 30 mA (150 mA surge) per diode, Vf < 0.4V @ 1mA. Since
you did not describe the exact SMD case, your diode is either a Panasonic
MA716 (SC-59 case) or MA742 (SC-70 case). Digikey ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
lists both MA716 ($0.61) and MA742 ($0.64). These specs are similar to
the Philips discrete Schottky series BAT81, BAT82, BAT83. Or perhaps SD101
(Diode, Inc.) might be tried.




QUESTION NO.
P75-5: How do I open the case of an Apple ColorSync 17 inch Monitor
without breaking the plastic tabs?

If you mean the
covers over the Torx screw channels on either side of the rear housing, these
must be squeezed using one hand, until they bow outward just enough, for the
center to be grabbed using the other hand, and removed. A tool will
gouge or snap them. Removal of the rear housing is a complicated
process. I strongly recommend getting the document for the ColorSync 17
from [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] before proceeding further, and
following the disassembly instructions carefully.




QUESTION NO.
P612-7: Power Computing/Sony GDM-20F03 monitor FCC AK8GDM20F03.
Powers up, then two orange LEDs flash on/off. No HV, no video.
Partial solution: On the main deflection board, in the P/S section,
check/replace Q645, C4833/ECG2582 (all junctions shorted); Q647, C4833/ECG2582
(all junctions shorted); R638, two Micron 0.1 ohm, 1/2W wired in parallel
(both open); and away from the P/S, IC402, LA6500 (exploded). After replacing
the above parts, green LED came on, HV began to come up, then IC402. LA6500,
exploded again and the (left?) orange LED flashed on/off (the other stayed
off).

Electronix Supply
House 800-223-3205 has a diagram for Sony AK8GDM20E01 for $29.95. Maybe
it is similar to your unit.

GDM20F03 is a
different chassis from GDM20E01. Get the Sony service manual for the
GDM20F03 from a Sony distributor, Sony part number 9-978-509-01.




QUESTION NO.
P67-5: Acerview 79g, 7279g JVP7279g monitor is dead.
Replaced Q314 (hot) Q321 (f640) in main pcb and D701, D713 (2nu 7.l),
D611(1n5388b), still no power. Since I cannot get 1n5388b(5w zd), I
replaced with a rectifier, is it the reason?

Other than D611,
the replaced components are in the 180 Volt rail and Horizontal deflection
circuit (Q314 is for deflection), so also check RF3958 = 1 ohm/1 Watt,
fusible. Since Q321 also blew, check components in line with it,
including D315, D316, L303, L304, R346, R363, and R3820. It was a mistake to
have replaced the 200-Volt zener at D611 with a plain rectifier. Since
D611 is in series with opposing diode D612, now no current can flow in either
direction, similar to having left D611 open-circuit altogether. If you
powered up this monitor with a rectifier installed at D611, inductive voltage
spikes from T601 may have damaged Q602 and associated components (including
IC601), so check those components. If you cannot get 1N5388B, try replacing
D611 with an NTE 5166A replacement Zener. Another possible alternative
for D611 could be a transient voltage suppressor, like 1.5KE200A or NTE 4988.




QUESTION NO.
P67-10: ADI PD-959 monitor powers up, relays switch and front panel LED
responds as expected when attached to a PC but no filament or HV. No
burned components or cracked traces.

Found the answer I
was looking for in the archive - see P525-3. Replacing the transistors
without the flyback just resulted in a failure a few hours later. Also
watch the heatsink on the K1006, it is not flat and only makes edge contact
with the transistor body.




QUESTION NO.
P618-7: KTX CAE565SG monitor has no horizontal width adjustment and is
too wide. Found q304 leaky but cannot obtain replacement. It is a
FS12UM fet in a TO-220 case.

FS12UM is a 12 Amp
Mitsubishi FET, but that number is incomplete. There will be a suffix,
to indicate the voltage rating, (in 50V increments). Yours is probably
FS12UM-5, which is a 250 Volt, 12 Amp, 100 Watt device. Possible
substitutes for that device are ST Micro's FET, STP12NB30, listed by Mouser
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or perhaps IRF's IRF644, listed by Digikey
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P618-8: Several Dell P1728U monitors which have a non standard pin
configuration. Where can I get cables? I really do not want to
open them all and move the pins around.

The Dell P1728U is
a Mitsubishi-made chassis, and Mitsubishi uses a nonstandard pinout.
You might get cables from a Mitsubishi supplier, or check with KMR Technical
Services ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] about their cable VCDB-003.




QUESTION NO.
P614-7: Techmedia TCM-1764S monitor blows fuses. I found a short
on the drive FET for switching supply. Transformer believed to have
short in primary. The numbers on the transformer (top to bottom) are
TCM-1764S then EH-9705. I need a cross or source for this
transformer.

It is not usual for
the switching transformer to be short circuited. The usual reason why
the switching FET in the power supply goes short circuit again is because of
a defective 3842 IC. Usually the resistor.022 ohms in the FET's source
goes open circuit as well so check this.




QUESTION NO.
P613-5: Mag DX17F monitor is not providing power to the main board and
supply board is making clicking noises. I removed R361 and degaussing
relay stopped clicking but a slight clicking still occurred, removed Q301
(NEC K1794) and clicking stopped. Measured voltage at junction of C303
and R304 and got 346Vp-p 210Vrms. Measured ~60.1Hz on pin 4 of IC301. I
searched for the K1794 part on the net - NEC was useless and no mention of
the part on the net at all. What is an acceptable replacement for this
FET? Am I on the right track?


الرجوع الى أعلى الصفحة اذهب الى الأسفل
SAD
نائب المشرف العام


عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:26 am





The full number on
that NEC FET is 2SK1794 (might sub NTE 2377), but it's probably not part of
your problem. Check if HOT Q109 is shorted. If yes, check/replace C120,
C123, Q116, D116, R177 = 1 ohm/2W, R181 = 120K/2W, and replace L105 if it is
discolored/shorted or rings bad (L105 is carried by many monitor repair
suppliers).




QUESTION NO.
P614-4: ADI Microscan 5PD, model VD-697 monitor, no FCC. When
first brought in, the power LED turn YELLOW when power on, but no HV.
The HOT (Q805), 2SC5515 (Panasonic) was shorted. As I cannot find the
original part here, I replaced with a 2SC3997 which has a higher rating on
the IC. Now the power LED turn to GREEN and stay on, but the HV fire up
and cut off after 2 seconds. No display, the green LED is ON.

It sounds like FCC#
BR8VD-697P, in which case, Q805 (2SC5515) is for the horizontal yoke
deflection. Check D924, for the 200V line, R511 = 2.2 ohm/0.5W, also
the B+ Regulator FET Q501, and associated components ZD501 & R501.

A good tip in these
sort of cases is to unplug the tube panel, because usually some protection
has taken over. ie. ABL or X-RAY. If it stays on this will give you a
chance to fault find.




QUESTION NO.
P614-5: Compaq V55 612 monitor. I need a sub for IC KA2S0680 in
the power supply.

One can substitute
KA2S0880 for KA2S0680. For either of these IC's, try LJ Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] may be mis-spelled as KA250680, etc), B&D Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P614-2: Acer 7276e monitor, the power light goes on then cuts back to
half intensity then fades out completely. The neck on the tube flashes
a bright light and fades as well, all within 15 seconds. I disconnected
all cables except the flyback from the motherboard but get the same
results.

If HOT Q302 has
shorted, or microfuse J013 is blown, check the components listed in the
answer for question P68-5, as well as Q316. Besides microfuse J013,
there are several other microfuses to check (F701, F702, F703, F704;
FR101). A shorted vertical IC (TDA8351) or video driver IC (LM2405) are
fairly common, also.




QUESTION NO.
P613-9: HP Pavillion D5258A monitor chassis code C5B. Need the
value of R865.

My schematic for
Tatung's chassis C5B is extremely poor, but if R865 is the resistor coming
from pin 6 of the 3842 IC, it appears to be 27 ohms, 1/4 Watt.




QUESTION NO.
P613-3: Sony GDM-20SE2T monitor, bright raster showing retrace lines.
Is this unit similar to the GDM20E03 and should I look for the infamous IC420
(CXA1907S)? What should a reasonable G2 voltage range be?

Since the FCC# is
AK8GDM20E03 for the 20SE2T, it should be clear that GDM20E03 is similar, and
yes, IC420 is a potential cause of that problem. Depending on the G1,
CRT, and high-impedance probe, a 170-350 Volts G2 voltage range might be
seen, in good units.




QUESTION NO.
P612-6: CTX x70 monitor FCC dbl1795vl. I need the value and part
number of Q401.

For FCC# DBL1795VL,
I show Q401 as Mitsubishi's FS3KM-18, an N-channel Mosfet, rated 900V, 3A,
30W, Rds[on] < 4 ohm. Try B&D Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for
the original, or possibly get Toshiba's 2SK2700T from Digikey
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P518-1: I need a source for flyback transformers and other parts for
Pionex monitors.

Get the FCC ID off
the back of the monitor then go to the fed site ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and
look up the id number, it will tell you who actually built the monitor.
There is also a site for the UL code that will get you the same info.




QUESTION NO.
P68-5: Acer 7276e monitor w/ vertical deflection failure. Cannot
find source or replacement for Q301 bss89 fet. Also need value of
R329.

R329 = 10K; Q301,
FET BSS89, can be replaced by a Philips BSN254 (not BSN254A).
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing BSN254 and BSS89, online.
Before going further, replace the root cause, C327 = 220 pF/2KV (3KV
replacement preferred). Also check R326 = 3.9K, R328 = 4.7K, R241 =
10K, ZD210 = 5.1V zener, J013 (3 Amp picofuse), D308 = UG4D, HOTQ302 =
2SC5048, and IC201 = TDA4858.




QUESTION NO.
P68-8: KDS VSx-7 monitor, the power light comes up, but no image.
R902 and R901 burnt. I need the value and are these the only parts that are
defective?

The FCC# should be
EVOKD-1730 for this KDS model. R901 = 27K ohm, R902 = 12K ohm. These
resistors burn because the flyback transformer KFS-61411A is bad; get a
replacement FBT from KDS (Korea Data Systems). Also check R903 = 47K, R904 =
12K, Q901, Q902, and if R904 has also burned, then check or replace IC401.




QUESTION NO.
P523-4: Gateway EV900 x19001 Monitor will not power up. Previous
repair attempt abandoned and R773 removed. Anyone know the value?

R773= 2.7K ohm,
.25watt.

On my chassis, R773
begins with a brown band so it is not 2.7k (the rest is burnt).




QUESTION NO.
P67-1: Hewlett Packard D2818A monitor FCC A3LCMG737. Need values
of Q408, R453, R455, D418, burned.

R453 = 22 ohms;
R455 = 2.2 ohm (fusible); D418 = 1N4148; Q408 = IRF740. Also check D417
= UF5404, if these others were damaged.




QUESTION NO.
P67-8: Daewoo cmc-1707b monitor. I need the values of R468 and
R462 which are burnt out on ABL circuit and a model number for the FBT.

R462 = 4.7K, R468 =
3.3K. The FBT should be either ZTFJ54006A or FFA87017U, but before
replacing, check that the HV anode has not shorted within the CRT itself.




QUESTION NO.
P531-8: Samtron 4Bi monitor (Basic CKA4227L), FCC A3LCKA422, initially
the image was displayed on the center of the screen and was approximately 2
inches in height and 4 inches in width and also two bright horizontal lines
on the top and the bottom of the image. All adjustments on the panel
except for contrast and brightness were inoperative. I replaced
C6271000uF 16V, C306470uF 16V, C308470uF 16V and vertical IC301TDA9302H.I now
have normal horizontal width which can be adjusted but the vertical height
remains the same ( i.e. 2 inches ) with the two bright lines. Now the
controls on the panels are O.K. but whatever vertical adjustments I try to
make seem to take effect in between the two white lines as if the lines were
a limiting frame of some sort without any changes to the image's
height. All the capacitor I replaced had low capacitance.

Check for a
leaky/shorted diode between pins 2 & 6 of the TDA9302H, or a bad
capacitor between pins 3 & 6 of the TDA9302H. Either of those
faults could prevent the vertical output at pin 5, from having full
deflection voltage. If these are OK, see if the vertical output signal
from IC401 is providing a good sawtooth waveform.




QUESTION NO.
P517-1: Daewoo CMC-1707B monitor. I need values for R468 and R469 which
are badly burnt.

According to the
schematic R468 is 3.3k and R469 is 75k 5%.




QUESTION NO.
P531-1: Packard Bell 2020 monitor will not power up. SPDT relay
clicks approx twice per second, with power LED flashing in time with
it. After approx 30 seconds the clicking/flashing slows down and stops
altogether and power LED glows solid yellow albeit dim but unit is completely
non functional. I checked the relay and surrounding electrolytics but
all seem OK.

I checked through
the high voltage circuit and found a shorted horizontal output
transistor. The damper diode checks out fine. I replaced the
transistor and the monitor has been working fine ever since.




QUESTION NO.
P525-3: ADI pd-959 monitor cuts the feeding. Had bad Q831
(BU2508DF), believe this is not original. Also bad Q567 (K1006) and
R866 (2 ohms). Replaced these components and powered up, blew Q831
again.

Q831 is BU2520DF,
but even the original Q831 may still blow. The PD-959 is known for
getting defective flyback transformers, that destroy those components.
If BU2520DF is not the fix, the FBT numbers are FEA662 or LZ250A000P. If a US
source is needed, try Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or LJ Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P525-7: Daytek DT-1731D monitor, FCC EWBOC17DB02; need the value of
R634.

R634 = 3.3K
ohm. But if R634 is burnt, the FBT is probably also bad.




QUESTION NO.
P516-7: ADI Microscan VD-697 monitor, blue & green show fine but
red is missing from both normal display and the OSD. Internal Signal
connectors appear fine.

Replace the drive
transistor (most probably on a heatsink) for the R gun on the chroma
board. Also check the big resistors on the chroma board for O/C.




QUESTION NO.
P54-3: Sony GDM-400PS monitor has a wavy picture in all mode. Is
IC007 CXA2043Q causing the problem?

Yes it is IC007
causing this fault. I repair a high volume of these monitors badged as
Compaq. It is the deflection process I.C. and this is a common fault.




QUESTION NO.
P521-9: Applevision 750AV monitor needs a flyback transformer. I
need a part number or size equivalent. I know it is made by Sony.

If this is an M2942
chassis, the flyback is number Y265065C.




QUESTION NO.
P522-4: Compaq v700 monitor dead. AC coming in is ok, the power
switch is working ok. I have to bleed cap c907 or mt huntron keeps
blowing a fuse.

There are several
CTX chassis called VL700, so without the FCC number, my info may not be for
your chassis. For FCC DBL1769E, I show a fix for 'dead', changing the
HOT Q313, P-FET Q306, R362, and cap C340. For FCC DBL1765S, a fix for 'dead',
caused by a tiny shorted 0.01uF cap, C671.




QUESTION NO.
P522-7: Techmedia TCM-1764S monitor blows fuses. Checked bridge
rectifier and filter cap both are good. Worked my way to the transformer
where some kind of switching transistor?? is on the input. This has a dead
short between all leads; the number on the part is in the following order top
to bottom 2 N 72 k2333. What are the specs/pinout or cross for this
transistor.

This sounds like
2SK2333, a Shindengen N-ch. MOSFET, TO220F with pinout GDS, rated 700 Volts,
6 Amps, 50 Watts, Rds < 2 ohms. Possible subs include FS7KM-14A (or
-16A) or FS7TM-16; or, with insulation hardware, FS7UM-14A (or -16A) or
STP6NB80.




QUESTION NO.
P522-9: Princeton E070 monitor. The flyback seems to be bad, I replaced
the HOT a few times. I get a picture on the screen for about 3 seconds
before the H.O.T. goes out (burns up). I need a source for the
flyback. I checked the power supply area diodes, resistors are
good. Only other thing is a diode could be failing under load.

If this Princeton
is FCC EVOKD-1730, the chassis was made by Korea Data Systems (KDS), and the
flyback is KFS61411A. You could order this from Princeton itself, or
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If these are not options, KDS could be
contacted directly, and they do sell the flybacks (often more cheaply) for
this FCC chassis, but ONLY for KDS models, like the KDS VS-7, not for
Princeton OEM's. Be advised that KDS has issued a modification on this
chassis, if the flyback is replaced, changing a number of resistors, diodes,
and capacitors, to improve flyback survival. Tech support should be able to
provide this information, or you could get Upgrade Kit#4 for the KD1730
chassis, from Nationwide.




QUESTION NO.
P514-1: I need a North American supplier for IC M0C2A60005, from the
power supply section of an Apple monitor.

I believe this
refers to MOC2A60-5, typically used as AC1 in the Applevision/Colorsync
Displays. This Motorola "Power Optoisolator" (a type of
solid-state relay) has a Triac rated for 2 Amps output, but this device has
disappeared from the market. If you wish to purchase many pieces, it
may be worthwhile inquiring from DERF ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If not many
devices are needed, Omron makes a version of their G3MB solid-state relay,
the G3MB-202PEG-4-DC20MA, which is a cross for the MOC2A60 types. Omron
has direct ordering available, in North America, via their website
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If the drive current being applied to the Omron's
IR-LED should be a bit low, to operate a given device, try reducing the value
of RP31 somewhat.




QUESTION NO.
P517-7: Compaq 480P monitor FCC GZM1323. Need a source or a
replacement for a V815 (THD400 transistor), located in horizontal circuit.

THD400 is not
obtainable, but Fimi has suggested the following substitution. Change
V815 from a THD400, to 2SC3998, and also do the following modification.
Install another retaining clip and mica insulator (with heatsink grease) on
new V815. Remove V841, and capacitors C883 & C884, from circuit.
Install a jumper in place of C884.

In response,
performed the modification but now the new transistor runs extremely hot and
monitor will eventually shut down.




QUESTION NO.
P515-1: Hewlett Packard 5259A monitor Chassis C7B has no width or
pincushion adjustment. Thanks to your tip, I found D434
(DMV32)leaky. My problem now is finding a replacement. Who carries this
part and is there a substitute?

DMV32 (DMV32A,
DMV32B, etc) dual diodes are in a TO220 case, rather than the TO3P or TO3PML
cases often used for such duals. A possible sub is the Sanken FMP-2FUR, but
it may be even harder to find. Try LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for DMV32B.




QUESTION NO.
P515-4: Need the value of R569 in Gateway CPD15F13 monitor.

R569 = 68 ohm, 1
Watt, 5%, flameproof.




QUESTION NO.
P515-10: Nimble NB-1726VQ monitor I think it was made by KFC Kuo Fong
CORP. It was blowing the main fuse. I found transistor at
location Q506 in the power supply shorted out. The part number on the
transistor is NEC K2141 I can not find a cross Ref # for it. Is there any
thing else I should look at before I replace the transistor?

The full number of
this Mosfet is 2SK2141, so inquire for it using the full number. This
FET is rated at 600 Volts, 6 Amp, 35 Watt, Rds[on] < 1.1 ohm, Ciss = 1150
pF. If your suppliers do not stock 2SK2141, you could try IRFIBC40GLC,
or an IRFBC40A with insulating hardware. Digikey Corp. ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
carries the IRF lineup. If the FET was shorted, I would check any
resistors or diodes/zeners off the gate lead, and if any of these are bad,
also check the FET driver IC. You might also ring the primary of the
SMPS transformer, in case of a shorted winding.




QUESTION NO.
P57-2: Compaq P110 model 630 monitor, the lower half stretches and
bounces and eventually puts the monitor into standby. Also, is there a
Sony crossmatch?

I believe this is a
Sony N3 chassis, similar to the Sony GDM-500PS. Check out the CXA2043Q
IC.




QUESTION NO.
P514-4: Mitsubishi Diamond View (1772E) monitor FCC
JVP7276E. I need the value of c327.

C327 = 220 pF/2KV.
You might replace this with a 3KV-rated capacitor.





QUESTION NO.
P510-1: Goldstar StudioWorks 76i. Replace D915 which was shorted
and CVA2422 that was burned by a new average diode substituted and for a new
CVA2422TL. In less than 5 seconds the CVA2422TL burned again and the
diode little time later. The exits of the supply power for 175V and 80V
were very low.

If by 'average
diode', you mean a standard-recovery rectifier, that would be too slow.
I believe D915 is a fast-recovery type rectifier, Trr < 250
nanoseconds. Also check the electrolytic filter capacitor off pin 11 of
the CVA2422T, and the filter capacitor off the cathode of D915, for damage.





QUESTION NO.
P59-7: I need the value of R935 on a Daewoo CMC-710B monitor
mainboard.

R935 = 82K.
It is part of the ABL circuit, off the FBT, so the FBT is suspect, if it
burned.





QUESTION NO.
P58-5: I need the part number of Q527 in a Sony CPD-15F13
monitor.

The CPD-15F13 is
usually a Sony 15SF1, in which case, Q527 = 2SD1640Q (Sony p/n#
8-729-023-28). This is a diode-protected NPN Darlington transistor,
Vcbo = 120 Volts, Vceo = 100 Volts, 3 Amp, 1.2 Watt, TO-126 case. The
'Q' indicates a gain bracket between 4000 and 10,000. Besides Sony
distributors, 2SD1640 itself is listed by MCM Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
Dalbani ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and others.





QUESTION NO.
P57-4: H.P. D5259a monitor has no width or pincushion control.
All caps check OK and have found no shorts or opens.

First, HP has been
marketing different chassis under the same model numbers, and D5259A is one
of those models, so you are inviting problems if you do not also provide the
chassis code (or FCC). For D5259A chassis C7B, I would check for
reverse leakiness or shorts in Q470 or the modulator diode half of dual diode
D434, and check out L471. If this gives no help, check the E/W signal
out of pin 24 of IC401 = TDA9109, and if bad, try replacing the IC. If your
D5259A is chassis C711, try checking D702 & D710.





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مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:29 am





The full number on
that NEC FET is 2SK1794 (might sub NTE 2377), but it's probably not part of
your problem. Check if HOT Q109 is shorted. If yes, check/replace C120,
C123, Q116, D116, R177 = 1 ohm/2W, R181 = 120K/2W, and replace L105 if it is
discolored/shorted or rings bad (L105 is carried by many monitor repair
suppliers).




QUESTION NO.
P614-4: ADI Microscan 5PD, model VD-697 monitor, no FCC. When
first brought in, the power LED turn YELLOW when power on, but no HV.
The HOT (Q805), 2SC5515 (Panasonic) was shorted. As I cannot find the
original part here, I replaced with a 2SC3997 which has a higher rating on
the IC. Now the power LED turn to GREEN and stay on, but the HV fire up
and cut off after 2 seconds. No display, the green LED is ON.

It sounds like FCC#
BR8VD-697P, in which case, Q805 (2SC5515) is for the horizontal yoke
deflection. Check D924, for the 200V line, R511 = 2.2 ohm/0.5W, also
the B+ Regulator FET Q501, and associated components ZD501 & R501.

A good tip in these
sort of cases is to unplug the tube panel, because usually some protection
has taken over. ie. ABL or X-RAY. If it stays on this will give you a
chance to fault find.




QUESTION NO.
P614-5: Compaq V55 612 monitor. I need a sub for IC KA2S0680 in
the power supply.

One can substitute
KA2S0880 for KA2S0680. For either of these IC's, try LJ Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] may be mis-spelled as KA250680, etc), B&D Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P614-2: Acer 7276e monitor, the power light goes on then cuts back to
half intensity then fades out completely. The neck on the tube flashes
a bright light and fades as well, all within 15 seconds. I disconnected
all cables except the flyback from the motherboard but get the same
results.

If HOT Q302 has
shorted, or microfuse J013 is blown, check the components listed in the
answer for question P68-5, as well as Q316. Besides microfuse J013,
there are several other microfuses to check (F701, F702, F703, F704;
FR101). A shorted vertical IC (TDA8351) or video driver IC (LM2405) are
fairly common, also.




QUESTION NO.
P613-9: HP Pavillion D5258A monitor chassis code C5B. Need the
value of R865.

My schematic for
Tatung's chassis C5B is extremely poor, but if R865 is the resistor coming
from pin 6 of the 3842 IC, it appears to be 27 ohms, 1/4 Watt.




QUESTION NO.
P613-3: Sony GDM-20SE2T monitor, bright raster showing retrace lines.
Is this unit similar to the GDM20E03 and should I look for the infamous IC420
(CXA1907S)? What should a reasonable G2 voltage range be?

Since the FCC# is
AK8GDM20E03 for the 20SE2T, it should be clear that GDM20E03 is similar, and
yes, IC420 is a potential cause of that problem. Depending on the G1,
CRT, and high-impedance probe, a 170-350 Volts G2 voltage range might be
seen, in good units.




QUESTION NO.
P612-6: CTX x70 monitor FCC dbl1795vl. I need the value and part
number of Q401.

For FCC# DBL1795VL,
I show Q401 as Mitsubishi's FS3KM-18, an N-channel Mosfet, rated 900V, 3A,
30W, Rds[on] < 4 ohm. Try B&D Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for
the original, or possibly get Toshiba's 2SK2700T from Digikey
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P518-1: I need a source for flyback transformers and other parts for
Pionex monitors.

Get the FCC ID off
the back of the monitor then go to the fed site ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and
look up the id number, it will tell you who actually built the monitor.
There is also a site for the UL code that will get you the same info.




QUESTION NO.
P68-5: Acer 7276e monitor w/ vertical deflection failure. Cannot
find source or replacement for Q301 bss89 fet. Also need value of
R329.

R329 = 10K; Q301,
FET BSS89, can be replaced by a Philips BSN254 (not BSN254A).
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing BSN254 and BSS89, online.
Before going further, replace the root cause, C327 = 220 pF/2KV (3KV
replacement preferred). Also check R326 = 3.9K, R328 = 4.7K, R241 =
10K, ZD210 = 5.1V zener, J013 (3 Amp picofuse), D308 = UG4D, HOTQ302 =
2SC5048, and IC201 = TDA4858.




QUESTION NO.
P68-8: KDS VSx-7 monitor, the power light comes up, but no image.
R902 and R901 burnt. I need the value and are these the only parts that are
defective?

The FCC# should be
EVOKD-1730 for this KDS model. R901 = 27K ohm, R902 = 12K ohm. These
resistors burn because the flyback transformer KFS-61411A is bad; get a
replacement FBT from KDS (Korea Data Systems). Also check R903 = 47K, R904 =
12K, Q901, Q902, and if R904 has also burned, then check or replace IC401.




QUESTION NO.
P523-4: Gateway EV900 x19001 Monitor will not power up. Previous
repair attempt abandoned and R773 removed. Anyone know the value?

R773= 2.7K ohm,
.25watt.

On my chassis, R773
begins with a brown band so it is not 2.7k (the rest is burnt).




QUESTION NO.
P67-1: Hewlett Packard D2818A monitor FCC A3LCMG737. Need values
of Q408, R453, R455, D418, burned.

R453 = 22 ohms;
R455 = 2.2 ohm (fusible); D418 = 1N4148; Q408 = IRF740. Also check D417
= UF5404, if these others were damaged.




QUESTION NO.
P67-8: Daewoo cmc-1707b monitor. I need the values of R468 and
R462 which are burnt out on ABL circuit and a model number for the FBT.

R462 = 4.7K, R468 =
3.3K. The FBT should be either ZTFJ54006A or FFA87017U, but before
replacing, check that the HV anode has not shorted within the CRT itself.




QUESTION NO.
P531-8: Samtron 4Bi monitor (Basic CKA4227L), FCC A3LCKA422, initially
the image was displayed on the center of the screen and was approximately 2
inches in height and 4 inches in width and also two bright horizontal lines
on the top and the bottom of the image. All adjustments on the panel
except for contrast and brightness were inoperative. I replaced
C6271000uF 16V, C306470uF 16V, C308470uF 16V and vertical IC301TDA9302H.I now
have normal horizontal width which can be adjusted but the vertical height
remains the same ( i.e. 2 inches ) with the two bright lines. Now the
controls on the panels are O.K. but whatever vertical adjustments I try to
make seem to take effect in between the two white lines as if the lines were
a limiting frame of some sort without any changes to the image's
height. All the capacitor I replaced had low capacitance.

Check for a
leaky/shorted diode between pins 2 & 6 of the TDA9302H, or a bad
capacitor between pins 3 & 6 of the TDA9302H. Either of those
faults could prevent the vertical output at pin 5, from having full
deflection voltage. If these are OK, see if the vertical output signal
from IC401 is providing a good sawtooth waveform.




QUESTION NO.
P517-1: Daewoo CMC-1707B monitor. I need values for R468 and R469 which
are badly burnt.

According to the
schematic R468 is 3.3k and R469 is 75k 5%.




QUESTION NO.
P531-1: Packard Bell 2020 monitor will not power up. SPDT relay
clicks approx twice per second, with power LED flashing in time with
it. After approx 30 seconds the clicking/flashing slows down and stops
altogether and power LED glows solid yellow albeit dim but unit is completely
non functional. I checked the relay and surrounding electrolytics but
all seem OK.

I checked through
the high voltage circuit and found a shorted horizontal output
transistor. The damper diode checks out fine. I replaced the
transistor and the monitor has been working fine ever since.




QUESTION NO.
P525-3: ADI pd-959 monitor cuts the feeding. Had bad Q831
(BU2508DF), believe this is not original. Also bad Q567 (K1006) and
R866 (2 ohms). Replaced these components and powered up, blew Q831
again.

Q831 is BU2520DF,
but even the original Q831 may still blow. The PD-959 is known for
getting defective flyback transformers, that destroy those components.
If BU2520DF is not the fix, the FBT numbers are FEA662 or LZ250A000P. If a US
source is needed, try Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or LJ Enterprises
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]




QUESTION NO.
P525-7: Daytek DT-1731D monitor, FCC EWBOC17DB02; need the value of
R634.

R634 = 3.3K
ohm. But if R634 is burnt, the FBT is probably also bad.




QUESTION NO.
P516-7: ADI Microscan VD-697 monitor, blue & green show fine but
red is missing from both normal display and the OSD. Internal Signal
connectors appear fine.

Replace the drive
transistor (most probably on a heatsink) for the R gun on the chroma
board. Also check the big resistors on the chroma board for O/C.




QUESTION NO.
P54-3: Sony GDM-400PS monitor has a wavy picture in all mode. Is
IC007 CXA2043Q causing the problem?

Yes it is IC007
causing this fault. I repair a high volume of these monitors badged as
Compaq. It is the deflection process I.C. and this is a common fault.




QUESTION NO.
P521-9: Applevision 750AV monitor needs a flyback transformer. I
need a part number or size equivalent. I know it is made by Sony.

If this is an M2942
chassis, the flyback is number Y265065C.




QUESTION NO.
P522-4: Compaq v700 monitor dead. AC coming in is ok, the power
switch is working ok. I have to bleed cap c907 or mt huntron keeps
blowing a fuse.

There are several
CTX chassis called VL700, so without the FCC number, my info may not be for
your chassis. For FCC DBL1769E, I show a fix for 'dead', changing the
HOT Q313, P-FET Q306, R362, and cap C340. For FCC DBL1765S, a fix for 'dead',
caused by a tiny shorted 0.01uF cap, C671.




QUESTION NO.
P522-7: Techmedia TCM-1764S monitor blows fuses. Checked bridge
rectifier and filter cap both are good. Worked my way to the transformer
where some kind of switching transistor?? is on the input. This has a dead
short between all leads; the number on the part is in the following order top
to bottom 2 N 72 k2333. What are the specs/pinout or cross for this
transistor.

This sounds like
2SK2333, a Shindengen N-ch. MOSFET, TO220F with pinout GDS, rated 700 Volts,
6 Amps, 50 Watts, Rds < 2 ohms. Possible subs include FS7KM-14A (or
-16A) or FS7TM-16; or, with insulation hardware, FS7UM-14A (or -16A) or
STP6NB80.




QUESTION NO.
P522-9: Princeton E070 monitor. The flyback seems to be bad, I replaced
the HOT a few times. I get a picture on the screen for about 3 seconds
before the H.O.T. goes out (burns up). I need a source for the
flyback. I checked the power supply area diodes, resistors are
good. Only other thing is a diode could be failing under load.

If this Princeton
is FCC EVOKD-1730, the chassis was made by Korea Data Systems (KDS), and the
flyback is KFS61411A. You could order this from Princeton itself, or
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If these are not options, KDS could be
contacted directly, and they do sell the flybacks (often more cheaply) for
this FCC chassis, but ONLY for KDS models, like the KDS VS-7, not for
Princeton OEM's. Be advised that KDS has issued a modification on this
chassis, if the flyback is replaced, changing a number of resistors, diodes,
and capacitors, to improve flyback survival. Tech support should be able to
provide this information, or you could get Upgrade Kit#4 for the KD1730
chassis, from Nationwide.




QUESTION NO.
P514-1: I need a North American supplier for IC M0C2A60005, from the
power supply section of an Apple monitor.

I believe this
refers to MOC2A60-5, typically used as AC1 in the Applevision/Colorsync
Displays. This Motorola "Power Optoisolator" (a type of
solid-state relay) has a Triac rated for 2 Amps output, but this device has
disappeared from the market. If you wish to purchase many pieces, it
may be worthwhile inquiring from DERF ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If not many
devices are needed, Omron makes a version of their G3MB solid-state relay,
the G3MB-202PEG-4-DC20MA, which is a cross for the MOC2A60 types. Omron
has direct ordering available, in North America, via their website
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] If the drive current being applied to the Omron's
IR-LED should be a bit low, to operate a given device, try reducing the value
of RP31 somewhat.




QUESTION NO.
P517-7: Compaq 480P monitor FCC GZM1323. Need a source or a
replacement for a V815 (THD400 transistor), located in horizontal circuit.

THD400 is not
obtainable, but Fimi has suggested the following substitution. Change
V815 from a THD400, to 2SC3998, and also do the following modification.
Install another retaining clip and mica insulator (with heatsink grease) on
new V815. Remove V841, and capacitors C883 & C884, from circuit.
Install a jumper in place of C884.

In response,
performed the modification but now the new transistor runs extremely hot and
monitor will eventually shut down.




QUESTION NO.
P515-1: Hewlett Packard 5259A monitor Chassis C7B has no width or
pincushion adjustment. Thanks to your tip, I found D434
(DMV32)leaky. My problem now is finding a replacement. Who carries this
part and is there a substitute?

DMV32 (DMV32A,
DMV32B, etc) dual diodes are in a TO220 case, rather than the TO3P or TO3PML
cases often used for such duals. A possible sub is the Sanken FMP-2FUR, but
it may be even harder to find. Try LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or
Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for DMV32B.




QUESTION NO.
P515-4: Need the value of R569 in Gateway CPD15F13 monitor.

R569 = 68 ohm, 1
Watt, 5%, flameproof.




QUESTION NO.
P515-10: Nimble NB-1726VQ monitor I think it was made by KFC Kuo Fong
CORP. It was blowing the main fuse. I found transistor at
location Q506 in the power supply shorted out. The part number on the
transistor is NEC K2141 I can not find a cross Ref # for it. Is there any
thing else I should look at before I replace the transistor?

The full number of
this Mosfet is 2SK2141, so inquire for it using the full number. This
FET is rated at 600 Volts, 6 Amp, 35 Watt, Rds[on] < 1.1 ohm, Ciss = 1150
pF. If your suppliers do not stock 2SK2141, you could try IRFIBC40GLC,
or an IRFBC40A with insulating hardware. Digikey Corp. ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
carries the IRF lineup. If the FET was shorted, I would check any
resistors or diodes/zeners off the gate lead, and if any of these are bad,
also check the FET driver IC. You might also ring the primary of the
SMPS transformer, in case of a shorted winding.




QUESTION NO.
P57-2: Compaq P110 model 630 monitor, the lower half stretches and
bounces and eventually puts the monitor into standby. Also, is there a
Sony crossmatch?

I believe this is a
Sony N3 chassis, similar to the Sony GDM-500PS. Check out the CXA2043Q
IC.




QUESTION NO.
P514-4: Mitsubishi Diamond View (1772E) monitor FCC
JVP7276E. I need the value of c327.

C327 = 220 pF/2KV.
You might replace this with a 3KV-rated capacitor.





QUESTION NO.
P510-1: Goldstar StudioWorks 76i. Replace D915 which was shorted
and CVA2422 that was burned by a new average diode substituted and for a new
CVA2422TL. In less than 5 seconds the CVA2422TL burned again and the
diode little time later. The exits of the supply power for 175V and 80V
were very low.

If by 'average
diode', you mean a standard-recovery rectifier, that would be too slow.
I believe D915 is a fast-recovery type rectifier, Trr < 250
nanoseconds. Also check the electrolytic filter capacitor off pin 11 of
the CVA2422T, and the filter capacitor off the cathode of D915, for damage.





QUESTION NO.
P59-7: I need the value of R935 on a Daewoo CMC-710B monitor
mainboard.

R935 = 82K.
It is part of the ABL circuit, off the FBT, so the FBT is suspect, if it
burned.





QUESTION NO.
P58-5: I need the part number of Q527 in a Sony CPD-15F13
monitor.

The CPD-15F13 is
usually a Sony 15SF1, in which case, Q527 = 2SD1640Q (Sony p/n#
8-729-023-28). This is a diode-protected NPN Darlington transistor,
Vcbo = 120 Volts, Vceo = 100 Volts, 3 Amp, 1.2 Watt, TO-126 case. The
'Q' indicates a gain bracket between 4000 and 10,000. Besides Sony
distributors, 2SD1640 itself is listed by MCM Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
Dalbani ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] Nationwide ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] and others.





QUESTION NO.
P57-4: H.P. D5259a monitor has no width or pincushion control.
All caps check OK and have found no shorts or opens.

First, HP has been
marketing different chassis under the same model numbers, and D5259A is one
of those models, so you are inviting problems if you do not also provide the
chassis code (or FCC). For D5259A chassis C7B, I would check for
reverse leakiness or shorts in Q470 or the modulator diode half of dual diode
D434, and check out L471. If this gives no help, check the E/W signal
out of pin 24 of IC401 = TDA9109, and if bad, try replacing the IC. If your
D5259A is chassis C711, try checking D702 & D710.





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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:32 am





QUESTION NO.
P57-7: Gateway ev700 (made by LG) FCC BEJCB775B. I need a source
for FBT 6147z-1012c.

The FCC corresponds
to an LG chassis CA-65, similar to an LG CB775BN or Studioworks 775N.
Try an LG distributor with the FBT number, but it should be 6174Z-1012C, not
6147Z. Nationwide Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing flyback
6174Z1012C in their online inventory.





QUESTION NO. P53-1:
Sony CPD-17SF2 monitor was totally dead. After replacing HV trans, both
led blinking. No 12 DC, but 145 V and 75 V exist. Replacing IC602
(12 v regulator) did not help.

Check Mosfets Q503
and Q510, damper D501, and also check small signal diode D596 (near FBT) for
reverse leakiness; a 1N4148 can replace it. Some capacitors may be bad in
this area (start with C525, C540, C541, C592). Check for any blown fusible
resistors in the SMPS transformer secondaries, and for any hairline cracks in
the PC board traces.





QUESTION NO.
P411-7: NEC 5FG monitor switches on with green light lit , no EHT but
have outputs from power supply as follows: brown/184v red/90v
orange/28v, unsure if these voltages are correct.

If this 5FG is
JC-1741UMA, and you are measuring at K1, K2, K3 of power connector CN-K, I'd
expect to see 180V, 90V, 30V nominal.





QUESTION NO.
P51-8: Digital Research 0711-03 monitor, cannot adjust width (too wide)
or pincushion. I tried several caps.

Check Q203, Q204, Q205, Q206, D107, C108.
Some transistors might merely be leaky, not totally shorted/open.





QUESTION NO.
P51-7: AcerView 7176ie monitor, on start up a green tint appears and
after a short warm-up (approx 2 minutes) monitor resumes normal
operations. Replaced Caps 3950, 3951, 3952 and Cap 353. Repair
fixed intermittent video flickering but green tint is still present at start
up.

Check for bad
solder connections on the video board, especially on the video connectors and
on the grounds for the video shield. Also check C110, C101, C102, C104,
C175, and the nonpolarized caps C111, C131, C151, for low value and/or bad
ESR.





QUESTION NO.
P430-2: Daytek DT-1431 monitor, the screen has no display, no raster
and the power LED is blinking. All transistors checked good.

Check the screen,
brightness, and contrast controls. If that does not work check the
flyback transformer and recheck the horizontal output transistor.





QUESTION NO.
P427-1: Nec Multisync 4FG monitor powers on with solid GRN LED.
Bad static crackle on power up as the display flashes for a split
second. Part site might also help.

Start by checking
under the electrolytic capacitors for leaked fluid, conducting voltages to
various places and eating PCB traces. For that symptom, start with
C557, C556, & C793, but many can leak. Other common leakers include
C561, C554, C564, C516, C517. Clean up any leakage well, and repair any
blackened traces that got eaten by fluid.





QUESTION NO.
P427-2: Viewsonic p815 monitor (manufactured by Panasonic).
I need to find a source for a Motorola MHW3528 (triple video driver
amplifier). This hybrid ic contains the circuitry to drive the color
guns of the crt and is located on the crt board. I have tried most of
the sources listed in these faqs, but have had no luck in finding a
supplier. What other monitors/televisions use this part (so that I
might find a OEM source)?

Nationwide
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] lists MHW3528 in its online inventory. P815 is a
Panasonic GV3 chassis, so check for this IC in other GV3's, like the Panasonic
P110.





QUESTION NO.
P427-5: Sony cpd 200es monitor. I suspect your advice that the
main MPU is bad since the power LED flashes on and off. Where may I
locate a replacement for IC901? The part I have is ST7272N5B1/CUS or
Sony-47-16 422AH9740Z.

Contact a Sony
distributor, for Sony p/n# 8-749-014-36. This version replaces the
original Sony p/n#, which was very high in failure rate.





QUESTION NO.
P427-6: KDS VSx-7 Visual Sensations monitor FCC EVOKD-1730, power light
comes up, but no image. R304 burnt beyond recognition. I need the
value and is this the only part that is defective?

A Princeton here,
with FCC# EVOKD-1730, had R304 = 4.7 ohm, 1/2W. Also check D406 and
IC301. There was a design flaw in FCC# EVOKD-1730, that can damage R304
and IC301. KDS has recommended modification of the chassis, to replace
J301 with two 1N4002 rectifiers, wired in series, and replace R330 with two
resistors wired in parallel, with values of 180K and 200K ohms. Check
if KDS VSx-7 has had this upgrade.





QUESTION NO.
P424-7: Acer 7257c monitor has pincushion problem. Changed ic 201
tda4858, problem not solved.

Try checking
transistors Q302 and Q303 for short or reverse leakiness; you also might
check bipolar capacitor C316.





QUESTION NO.
P411-1: CTX VL700 monitor. Need alternative type for transistor
Q415 marked as type F444 but cannot identify this or find an equivalent.

I think the
transistor you are referring to is a SGSF444 made by ST (st.com) which I
believe it is obsolete. I do not know of a substitute.

SGSF444 crosses to
ECG2324 according to ECG212S Master Replacement Guide.





QUESTION NO.
P424-3: Hewlett Packard D3859A monitor has vertical tearing across the
entire screen and I 603 vert.out. IC TEA8172 gets extremely hot.
Replacing it did not help.

Check the capacitors around IC603,
especially C626 off the input. If there is ripple or noise on the power rails for the IC, this can
also cause problems, so check the filter caps. Also check zeners
ZD601 & ZD602. Sometimes, screen noise can
come from a faulty (noisy) KA3842 IC in the Power Supply.





QUESTION NO.
P419-7: What is the value of R608 in Digital PCXAV-TZ (Chassis CA-52)
monitor?

Electro Sound
carries this resistor and capacitors Part # 1-202-933-61/11.
800-441-6110 in New Jersey.





QUESTION NO.
P423-1: Gateway 2000 EV500 500-069CS monitor Chassis CA-46,
intermittently will power up, then enters shutdown. Can hear arcing
sound when unit enters shutdown. Arcing sound leaves when unit
works. Ftb? Crt? Part# for ftb-6174Z-1002A? Ground straps are
connected, cannot see any visible arcing when lights are turned off.
Strong guns when working.

There are two
versions of this chassis. One version has a two-piece flyback transformer,
with an HV diode module mounted next to the FBT. These are very
common-failure devices. LG Electronics (formerly Goldstar) distributors
can provide them, using your flyback's number, but they are rather expensive.





QUESTION NO.
P423-7: HP Pavillion D5258A monitor is dead. I need a source for
24lc211 IC which I suspect is the cause.

24LC1I is an I2C
serial Eeprom ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] So, if you indeed do need this IC,
you probably need it properly pre-programmed. This requires knowing the
OEM manufacturer (HP is not the OEM), and their corresponding model#.
However, be advised, that HP has used several different chassis (and from
different OEM's) in D5258A, and also D5259A, Pavilions. I personally
know at least four different chassis for D5258/A (could be more), from OEM's
like Philips, Daewoo, and Tatung. You'll need to use the FCC number off
your version (or failing that, the chassis code), to locate the OEM
manufacturer and their corresponding model, to get the properly programmed IC
from them.

Firstly it will
probably not be the EEPROM that is the problem. If it is a model made
by SAMPO check R024 2.2Mohm in the power supply. If it is a model made
by Tatung check D803 in the power supply secondary for S/C. Also on
this model check connector from control board to mainboard for faulty connection
especially the contacts in the connector at the mainboard. Also check
I801 in the power supply.





QUESTION NO.
P423-6: Mag DJ800 X19001 monitor had no HV. Transistor FS10SM had
open emitter, no other signs of damage in area so replaced it with an
available ECG-2331 and everything works but now concerned about adequate
rating. Need proper cross for transistor marked FS10SM 16A. Case is
TO-3PJ.

FS10SM-16A would be
a Mitsubishi N-channel MOSFET, rated 10 Amps, 800 Volts, so in actuality, it
does not have an emitter, and, yes, a bipolar device like ECG2331 is indeed a
bad cross. In fact, ECG2377 may not quite measure up. Try B&D
Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] for the original FS10SM-16A, or for a cross, you
might try an STW11NB80, which is listed by Mouser ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or an
IRFPE50, which Digikey ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] is listing.

Since posting the
question, I am embarrassed to report that I discovered the FS10SM-16A is an
Nchannel power mosfet. The "open emitter" as measured with a
meter was actually the source terminal. I re-installed the mosfet and
the monitor still worked fine. The actual "fix" was probably
the result of my re-flowing many of the solder joints in the HV area at the
same time as I replaced the mosfet with a transistor. (The raster was
slightly wider with the transistor installed so I assume the mosfet is part
of a HV control circuit).





QUESTION NO.
P323-4: Sceptre P773 monitor has a pincushion and width problems that
cannot be adjusted.

Check the High Voltage Poly caps in flyback
area for shorts or opens. (Note) These caps are fairly big in size.





QUESTION NO.
P419-6: Samsung synMaster 17Glsi, after warmup the screen goes blank,
indicator is green. Try to push BNC/D-sub in front panel no
response. If powered off for long times, same symptom occurred..
Also I need a cross reference for Transistor IRF PC40.

IRFPC40 is an
N-channel MOSFET, 600 Volt, 6.8 Amp, 150 Watt, Rds[on] < 1.2 ohm, TO247
case style. It is readily available; for example, from Digikey
([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] A cross reference for IRFPC40 could be ST Micro's
STW7NA60.

Replace 2kV caps
(G2,ground) on picture tube socket.





QUESTION NO.
P419-4: Acer 7154s monitor is dead with just a fast flashing green
led. C335 was burned, replaced with no result.

Check FET Q317; if
it has shorted, then check that L304 has not burnt/shorted, and that its
inductance has not dropped below about 0.7 mH. Also check D316 and
D317. Since C335 had burnt, check R214, IC201, and Q310 as well.





QUESTION NO.
P418-8: Cornerstone color 21 [nec,jc-2142umw] monitor. I replaced
Q581-2sc3998 and Q5g6- 2sk758. The high voltage is back but now the
side pin can only be corrected a little bit.

Assuming this brand
is like the NEC 6FG, try checking the pincushion daughterboard, on the left
side of the main board. First check for any leaking electrolytic
capacitors at this board, or where the input connectors are located.
Check if +12V and -12V are present on pins SA4 and SA5 of the connector. Also
check IC5S3, an LM324A-type op-amp, on the daughterboard, as this can
sometimes fail.





QUESTION NO.
P417-8: Seanix KM-730 monitor FCC ARFKM730 seems to be made by Sampo,
has all the video crammed into the center 4 inches of the screen, the very
middle is clear and an inch on either side is distorted.

I believe the
horizontal yoke is driven by Q730 in FCC# ARFKM730. It sounds like Q730
is leaky or breaking down. Besides Q730, also check the Horizontal
drive capacitor C757, drive transformer T703, box capacitor C761, and also
check for bad solder connections on these components and the horizontal yoke
connectors.

I may have not
described the problem correctly, the horizontal seems fine, it fills the
screen width perfectly, it is vertically where the problem is, like the
vertical height is misadjusted but with distortion on both top and bottom.





QUESTION NO.
P417-3: Gateway EV900-7000595 monitor is dead, will not power up, no
major parts shorted in power supply or hv circuit except VR501 is fried along
with R538 and R573. Also I need the value of VR501 (the ABL adjust
control located at the very back of the monitor, next to the flyback) and
R538 and R573.

VR501 = 20K, R573 =
68K, R538 = 1K. However, when these parts burn, it is often due to a bad FBT.
Or, sometimes, a missing 12V reference can cause a power supply overvoltage
situation; one cause of this can be if D315 goes open (not short).





QUESTION NO.
P411-8: Goldstar StudioWorks 76i monitor. I need a datasheet, sub
or source for IC 302 that has burnt, I think it is a video
amplifier.

ic302 is an
cva2422. I get mine from LG in OZ.





QUESTION NO.
P314-7: Acer 7176i monitor. I need the values for R348, R349,
R455 and the part number off D314.

R348=4.7k .5w, R349
=100k .25w, R455 =3k, D314 =rgp10d.





QUESTION NO. P411-4:
IBM 2124-001 monitor. I need a value for c335, c336 and r214.

This IBM is similar
to the Acer 7154e chassis. C335 = 220 pF/2KV, C336 = 0.01 uF/50V, and R214 =
15K ohms.





QUESTION NO.
P410-1: Acer 54E Monitor the display goes off in about a minute of
being on. Then it flashes on and off. C335 dark brown, D316 OK in
circuit, Q317 shorted. Replaced & burnt in no time. OK in
Circuit, L304 .8 ohms, R214 12.83Kohms, D317 OK in circuit.

If C335 and Q317
both burned again, first use a good-quality disk cap for C335, 220 pF at 3KV
is recommended. Along with Q317, the D317 and L304 form a boost
circuit, to raise the raw B+ (45V) going to the HOT. I do not trust
ohms readings to check L304, you need an inductance value; nor is in-circuit
testing D317 adequate. L304 is nominally "2 mH", but many
good L304's will measure 0.8 mH on an inductance meter. However, if the
inductance of L304 falls much lower than that value, the excess current will
blow Q317. Ultrafast rectifier D317 must be tested for reverse leakage
out-of-circuit. Replace it if any reverse leakage is observed.
Although the value of R214 = 15K ohm is not truly critical, in this
situation, I would replace it anyway. It seems out-of-spec; I would be
concerned that it has been damaged, and that your meter's resistance reading
may be quite different from its resistance value at high voltage and high
frequency. If that is the case, IC201 may be damaged as well, and need
replacing. Also check that the values of precision resistors R216 &
R220, going to the B+ sense pin (pin 4) of IC201, are still at the correct
value.





QUESTION NO.
P410-2: Acer 54E Monitor has a blinking green led and a clicking noise
on the board. Q310 B C E Out of Circuit + - .55, - + OL, + - .48, - +
OL, + - OL, - + OL, C335 Burnt, D316 OK Out of Circuit, L304 .8 ohms, R214
Burnt, D317 OK in circuit.

Because R214 = 15K
ohms is burnt, IC201 = TDA4858 probably needs replacing. Be sure to use
a good-quality disk cap for C335; although 220 pF/2KV is usually installed,
it is better to use a 3KV rating. Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] has
these, in the US. Check R216, R220, off pin# 4 of IC201, for value,
check D317 for leakiness, and check the inductance of L304. For that
Q310, I can't tell which pins go with which ohms, but it seems appropriate,
since this HOT has no internal damper.


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عدد المساهمات : 843
تاريخ التسجيل : 16/06/2010

مُساهمةموضوع: رد: Computer Monitor Repair    الخميس مايو 26, 2011 4:33 am





Because R214 = 15K
ohms is burnt, IC201 = TDA4858 probably needs replacing. Be sure to use
a good-quality disk cap for C335; although 220 pF/2KV is usually installed,
it is better to use a 3KV rating. Mouser Electronics ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] has
these, in the US. Check R216, R220, off pin# 4 of IC201, for value,
check D317 for leakiness, and check the inductance of L304. For that
Q310, I can't tell which pins go with which ohms, but it seems appropriate,
since this HOT has no internal damper.





QUESTION NO.
P46-1: Commodore 64 1702 monitor FCC BR99oy1702,UL277C. I need
value of R904=brown, black...., 1/2w and R908=red, red...., 1/2w located near
STR3125 reg in power supply board labeled GF-1003A (2/6).

R904=12K ohm,1/4w
and R908=220 ohm,1/4w.





QUESTION NO.
P49-1: emc sa-770 monitor. Replaced shorted q630 irf634a with sub
2sk526 and it shorted out too when gen. signal was applied within 1/2
minute. Other parts in hor. circuit check ok. Should I put in
ecg2900?

2SK526 is not quite
as good as IRF634A, but whenever Q630 shorts out, you should always replace
C635 and D632 (ECG576) as well, to prevent more failures. If the C635
was 22 uF/250V, EMC recommends dropping the value on the replacement to 10
uF/250V. Also check the solder on the three resistors near Q630, R66B,
R66C, R66F.





QUESTION NO.
P49-3: Compaq QVision 200 Monitor. When powered on the LCD displays
"HIGH VOLTAGE FAIL". I have heard if I change the metal
"box" containing the FBT etc. the problem will be fixed.
Where can I get it? Compaq denied having the parts.

Those chassis are
made by Philips/FIMI. As you learned, Compaq is a waste of time for
replacements. "HV Fail" is usually a bad Flyback, sometimes
the focus module, if you also see focus/brightness problems just before the
"HV Fail". Try places like LJ Enterprises ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] or
NEI ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] etc. These are very pricey items, so be sure
the numbers match with yours, as there are several versions. The
Flyback will have a number like AT2090-XX; focus module numbers will be like
926xx.





QUESTION NO.
P49-6: HP D2846 monitor, picture distortion in all modes.

If this HP is the
Sony chassis, first check for marginal/bad electrolytics. If this is
not the fix, try deflection processor CXA2043Q, Sony p/n# 8-752-078-48, on
the D board.





QUESTION NO.
P46-8: HPD2818A monitor FCC A3LCMG737, HV present, filament lights, no
picture except for a little scan just visible for a split second after power
on. Monitor responds to exit standby mode when connected to PC.
Cannot feel any static/HV build up on screen. G1 appears to have zero
volts, filament volts are a little low 5.8-9, tried up-ing this a little, no
effect (except filament brightened). Yes, its a blue label Samsung w/
digital on screen menus.

First, see if you
can bring back the image by raising G2 (screen) voltage. If this is all that is needed, tell
the customer not to be surprised if the CRT eventually gives out; it may be marginal. If
it is not low G2, check if the color guns are too high in voltage (over
100V).

Follow-up:
Tried raising G2 first thing. No luck. BLUE and GREEN gun voltages are too
high about 135-140V, RED looks OK at 85V.





QUESTION NO.
P46-5: Dell UltraScan 1000HS, Model D1025TM monitor will no longer
power up. About every 5-10 seconds it makes a high-pitched chirp.
Previously the monitor would only power on and give an orange light, even
with a signal connected.

First, check the
following components, Q507, Q520, Q501, D503, D516, D614, C622, and IC605. If
these are all OK, or if the flashing orange LED returns, suspect a bad CPU IC, IC901;
it has been a common failure in this Sony chassis.





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