Acer monitor green
lifetest
the monitor is good, except the text turns green sometimes, sometimes if I
tap the top the writing will turn normal (black). anyone have experience
with this problem?
Sam Goldwasser
Bad connections, probably on CRT neck board. Should be realtively easy
to find for someone with experience and who is aware of the SAFETY issues
in working on a monitor.
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DaveW
flaw?
At least a few years back, it was also suggested by someone
here, that the problems I was having with a 99c may be the
result of KNOWN bad solder joints on the CRT socket. I
re-soldered and no problems since.
I smell Class Action........
"lifetest" <life...@rogers.com> wrote in message
news:elCD9.149676$oRV....@news04.bloor.is.net.cable.rogers
.com...
Wayne
wrote:
Just did one recently - known problem with these. I ended up replacing
a lot of the bad caps, redoing all the bad solder, and changing D308
(leaky). Also drilled additional holes through the mainboard for more
(cooling) air flow for the caps near the heat sink (surrounding the
FBT) that go bad. Here is what I found on these...
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. 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(www.geocities.com/monitorss/), 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. 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. 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. 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. P323-9: Acer 7176ie monitor, when switched on, the power
comes, led light on and relay clicking but no raster. Checked B+, it
is normal. Measured the voltage across HOT, no voltage. Changed many
capacitors around hot/fbt, but still symptom. If there is no B+ to the
HOT collector, is the gate of the B+ regulator FET Q303 being driven?
If not, do the pair Q301 & Q346, and Q302, operate? Is the initial
drive signal emanating from pin 6, of IC304 (TDA4855), or is IC304
being shut down, due to low Vcc (pin 9), or by an Xray-protect input
(pin 2), or by taking HPLL2 (pin 31) low? Did those replaced
capacitors include C320 (disk cap), and electrolytics C307, C353; as
well as the trio C3950, C3951, C3952, and their associated 1 Mohm
resistors?
QUESTION NO. P1020-3: Acer 716ie monitor with pincushion distortion.
Pincushion control still works but cannot adjust enough. Replaced
C3950-3952, C353, C320 (100pF, 2KV), with no improvement. If this is
actually an Acer 7176ie, try checking Q312, Q313, and D308 for excess
reverse leakiness.
QUESTION NO. P103-3: Acer 7176ie equivalent (Elonex MN044) monitor
with intermittent shutdown. The vertical output from IC304 stops as
does the drive for B+ (drops to about 60 volts) to the high voltage
transformer hence the unit stops displaying. The horiz drive continues
to be produced. I replaced IC304 (TDA4855) and the fault remains. I do
not think it is in X-Ray protection as it still faults with pin 2 of
IC304 shorted to GND. Check the ceramic disk cap off the HOT
collector, C320 = 100 or 120 pF/3KV, and electrolytics C3950, C3951,
C3952 = 2.2 uF/450V, & C353 = 10 uF/450V. Also check the three megohm
resistors in parallel with C3950-C3952.
QUESTION NO. P51-9: A growing number of Acer 76ie monitors we
purchased for repair/resale have a thin vertical wavy line appearing
about three inches from the left side. Replace C315 1UF 100V, C3925
2.2 UF 450V, C3951 2.2 UF 450V, C3950 2.2 UF 450V, C353 10 UF 450V, C
607 100UF 50V.
QUESTION NO. P126-1: AcerView 7176ie 17" SVGA, made July 1996. During
warmup there is excessive highlight tearing, sometimes covers whole
screen in bright green tint. Sometimes accompanied with high pitched
whine (VGA freq. range). After a few minutes warm-up problem
disappears. Only happens after the monitor has cooled down for an
hour. Replaced all the caps on the color board, no help. Filament
voltage stays constant. Replace capacitors 3950,3951,3952. They are
near the heatsink around the FBT. I forget the value but they are
450V.
QUESTION NO. P929-5: AcerView 7176ie monitor. When turned on there is
fast clicking and blinking power LED on the front. Q306 was completely
shorted. I am having trouble finding a replacement transistor. The
case has C5048 on it. What caused the transistor to blow? The
transistor you are looking for is 2SC5048. It is listed in B&D
Enterprises catalog, 1-800-458-6053. For the cause check surrounding
diodes and capacitors. C5048 is a Toshiba 2SC5048, a 1500V, 12 Amp
HOT. Try B&D Enterprises (800-458-6053) or MCM (800-543-4330). In this
situation, always replace cap C307 = 1 uF/50V and ceramic disk cap
C320 = 100pF/2KV (it is better to use a 3KV rating); these caps, even
if marginal, can cause the HOT to blow. Also check D308, C315, C353,
C3950, C3951, C3952. If problems persist, check the coils (L304, L306,
L307, L308, etc), check for bad solder in the horizontal area or on
the connector pins for the video amp board.
QUESTION NO. P77-9: Acer 7176ie monitor. Replaced c3950, c3951, c3952
for intermittent video problem. Now unit has no horizontal size or
pincushion adjustments. All other functions work ok. First check
ultrafast rectifier D308 = FES8JT (600 V, 8 Amp, Trr < 35 nanosec); if
it is leaky, it is $4.34 from B & D Enterprises (800-458-6053). Always
replace ceramic cap C320 = 100 pF/ 2KV. If D308 is not the problem,
check out transistors Q310, Q312, Q313, Q314; diode D307; caps C609,
C610, C623; coils L306, L307; IC301.
QUESTION NO. P69-1: Acer 7176IE monitor, will not power up, and there
are no lights lit. I have 83vdc to the fet. To answer my own question,
I found Q601, shorted ebc, then IC601 had only 3.5v on pin 7. replaced
q601, ic601, and, had 11.5 volts on pin 7. Replaced c605=22x50v, this
allow the monitor to power up. At this time there is 17.5volts on pin
7 of ic601, and, all is well. Replaced c607=100x50v while you are
there. To add to my answer there was 167v on the drain of fet. This
monitor came back in three weeks with the same problem of no startup.
I found that d603 [1n4001], causes a low voltage condition at pin 7 of
ic601. All other componets checks out to be ok.
QUESTION NO. P319-2: Two AcerView 7176IE monitors that exhibit video
smear (a ghost effect on text characters and icons). For example when
when working with text documents the characters have a green tint and
a light grey shadow to the right of the characters. You need to
readjust the crt beam centering magnets.
Some Acer monitors will turn on and display the OSD menu WITHOUT the
signal cable plugged into a computer, and the menu is often rather
shaky. I assume this is due to the lack of proper sync pulses coming
in from the computer. I've seen this before and I consider it normal.
The OSD menu shouldn't shake at all when the monitor is plugged into a
computer and displaying a normal VGA image. Then the menu should come
on when you press one of the front panel buttons, and be completely
sharp and stable. One other important thing to check on these Acer
monitors --- where the external VGA signal cable attaches to the neck
board, there is often lots of bad solder. To check this you have to
remove the neck board shield first.
7176ie is also known as Acer 1768ie Check the neckboard for dry joints
on connectors, M101,M102,M106,M1910 also IC102 on neckboard for dry
joints. On main pcb check IC201 for dry joints If the hot Q306 has
blown then you should check C302 101K kV also D308 has a white mica
insulating washer that breaks down and develops holes which results in
high voltage arcing to ground. You should hear a loud tick then the
monitor shuts down even though the green led remains on. This can
result in hot Q306 blowing. Check the three 2.2 450V caps
C3950,C3951,C3952 and three 1meg Resistors R3950,R3951,R3953.
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).