AOC F22S _ LCD MONITOR _ TROUBLESHOOTING
No power
|
||||
Press power key and
look if the picture is normal.
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||||
NG
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||||
Please reinsert and make sure the AC of 100-240 is normal
|
NG
|
Reinsert or check
the power section
|
||
OK
|
||||
Measure U404
Vout=3.3V Q409 VC=1.8V
|
NG
|
Measure CN404 PIN5/6=3.3V?
Measure CN404
PIN3/9=5V?
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||
OK
|
OK
|
NG
|
Check power
section
|
|
X401 oscillate
waveforms are normal
|
Replace U404, Q409
|
|||
OK
|
NG
|
Replace X401
|
||
Replace U401
|
NO PICTURE. LED ORANGE
No picture
|
||
Measure U404 Vout=3.3V
Q409 Vc=1.8V
|
Ng
|
Replace U404, Q409
|
Ok
|
||
X401 oscillate waveforms are
Normal.
|
||
Ok
|
Ng
|
Replace X401
|
Check if the sync signal from computer is output and video cable is connected
normally.
|
||
Ok
|
Ng
|
Input the sync signal of
computer, or change the
cable
|
Replace U401
|
NO POWER. POWER BOARD
Check CN902 pin3=
12V
|
||
Ng
|
||
Check AC line volt
110V or 220V
|
Ng
|
Check AC input
|
Ok
|
||
Check the voltage of
C905A (+)
|
Ng
|
Check bridge
rectified circuit and F901 circuit
|
Ok
|
||
Check start voltage
for the pin3 of U901
|
||
Ok
|
Ng
|
Check R912,R904 and
Change U901
|
Check the auxiliary voltage is bigger
than 10V and smaller than
20V
|
||
Ok
|
Ng
|
Check U901
|
Check U901 pin8 PWM
wave
|
||
Ok
|
||
Check
Q901,R910,T901,D900,D901
|
W/LED. NO BACK LIGHT
Check C802 (+) =12V
|
||
Ok
|
Ng
|
Change Q802
|
Check
ON/OFF signal
|
||
Ok
|
Ng
|
Check main board
|
Check U801 pin6=12V
|
||
Ok
|
Ng
|
Change Q804 or Q809
|
Check the pin1 of
U801 have saw tooth wave.
|
Change U801
|
|
Check T801/T802 have
the output of square wave at short time
|
||
Ok
|
Ng
|
Check C801/C825/D815/D814
Check
C812/C826/D817/D816
|
Check the output of
T801/T802
|
||
Ok
|
Ng
|
Change T801/T802
|
Check connecter
& lamp
|
