AOC LM927U Service Manual page 37

2.) No Backlight
Check the pin1 of U201 have sawtooth wave
Check D201/D202 have the output of square ware at short time
Check the resonant wave of pin2 & pin5 for PT201/PT202
Check the output of PT201/PT202
Check C201 (+) =12V
NG
OK
Check ON/OFF signal
NG
OK
Check U201 pin9=12V
NG
OK
NG
OK
NG
OK
NG
OK
NG
OK
Check connecter & lamp
Change F902
Check main board
Change Q201 or Q202
Change U201
Check Q205/Q207/Q203/D201
Check Q206/Q208/Q204/D202
Check Q209/Q210/C213
Check Q211/Q212/C214
Replace PT201/PT202
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AOC LM927U