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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
MAKE SURE THAT
THE VARIABLE
OUTPUT IS NOT SHORTED
CHECK AC LINE
VOLT 120V OR 220V
NG
CHECK F901, SW901
OK
NO
CHECK LINE RECTIFIED
& SMOOTHED VOLT
CHECK IC101
PIN39,40,41, B+
DRIVER
YES
CHECK THE 56V OUTPUT
NG
CHECK BRIDGE
RECTIFIED
OK
NG
CHECK START C.K.T
R936
CHECK D925
OK
CHECK Q911
NG
OK
CHECK T901 O/P
Q911 FAILURE
OK
IC101 PIN30(ABOUT5V)
NG
CHECK 56V, 12V
6.5V CIRCUIT OUTPUT
OK
OK
CHECK IC901
NG
IC901 FAILURE
OK
CHECK SENSE RESISTENCE
ViewSonic Corporation
21
Confidential - Do Not Copy
G90fB-4