AOC 2230FH Service Manual page 41

22" LCD Color Monitor
8.2.2 Power Board
1) No power
Check AC line volt 110V or 220V
Check the voltage of C905 (+)
Check start voltage for the pin3 of U901
Check the auxiliary voltage is bigger than
10V and smaller than 20V
Check U901 pin8 PWM wave
Check Q901/D900/D903
OK NG
OK
NG
OK NG
NG
OK
OK
NG
Check AC input
Check bridge rectified circuit and F901 circuit
Check R904, R905, R906, Change U901
1) Check U901
2) Check R906/D908 circuit
Check U901
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AOC 2230FH