ViewSonic G90fB-4 - Power Supply Troubleshooting

6-12. Power supply trouble shooting chart
Before check SW.REG.Please refer to the power supply block diagram power supply output
:
(A) Variable output: 60V
(B) Constant output : 6.3V, 12V,83V，180.V，－12V
BEAD SET
ABNORMAL VARIABLE OUTPUT
NG
O
K
NG
O
K
O
K
NG
NG
O
K
O
K
O
K
N
G
O
K
N
G
YES
N
O
CHECK BRIDGE
RECTIFIED
CHECK START C.K.T
CHECK IC101
CHECK D925
CHECK Q911
Q
911 FAILURE
CHECK IC901
CHECK AC LINE
VOLT 120V OR 220V
CHECK F901, SW901
CHECK LINE RECTIFIED
& SMOOTHED VOLT
CHECK SENSE RESISTENCE
IC901 FAILURE
CHECK T901 O/P
MAKE SURE THAT
THE VARIABLE
O
K
OUTPUT IS NOT SHORTED
R936
PIN39,40,41, B+
DRIVER
6.5V CIRCUIT OUTPUT
IC101 PIN30(ABOUT5V)
CHECK 56V, 12
V
CHECK THE 56V OUTPUT
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