HCL HCM9LWAN21 Service Manual page 33

19"W LCD Color Monitor
8.2.2 Power Board
No power
Check L903 = 12V
Check AC line volt 110V or 220V
Check the voltage of C904 (+)
Check start voltage for the pin3 of IC901
Check the auxiliary voltage is bigger than
10V and smaller than 20V
Check IC901 pin8 PWM wave
NG
OK NG
OK NG
NG
OK
NG
OK
OK
NG
Check Q901/IC903/ZD902/IC904
Check AC input
Check bridge rectified circuit and F901 circuit
Check R903, R904, Change IC901
1) Check IC901
2) Check R909/D902/C906 circuit
Check IC901
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HCL HCM9LWAN21