20” LCD Color Monitor BenQ G2020HDA
51
Power Board
No power
Check CN902 PIN4.5 = 5V
Check AC line volt 110V or 220V
Check AC input
Check the voltage of C907 (+)
Check bridge rectified circuit and F901 circuit
Check start voltage for the pin8 of IC901
Check R904, R905, Change IC901
NG
Check the auxiliary voltage is bigger than
10V and smaller than 20V
1) Check IC901
2) Check R909/D901/C903 circuit
OK
OK
NG
Check D915/D916/IC902/IC903/ZD902/ZD901
OK
Check IC901 pin5 PWM wave
OK
Check IC901
NG
NG
NGOK
NG
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