AOC LM2028 Service Manual page 34

2) No Backlight
Check C225 (+) =12V
OK
Check ON/OFF signal
OK
Check U201 pin9=12V
OK
Check the pin1 of U201 have sawtooth wave
OK
Check D201 (-) have the output of square wave at short time
Check D202 (-) have the output of square wave at short time
OK
Check the resonant wave of pin2 & pin5 for PT201
Check the resonant wave of pin2 & pin5 for PT202
OK
Check the output of PT201
Check the output of PT202
OK
Check connecter & lamp
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NG
NG
NG
NG
NG
NG
NG
QQ:505966338
Check Main board
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
Change PT201, change PT202
Page 34 of 66
AOC LM2028