Power Supply Trouble Shooting Chart - ViewSonic Q51 series Service Manual

6.9 POWER SUPPLY TROUBLE SHOOTING CHART

BEFORE CHECK SW.REG. PLEASE REFER TO THE POWER SUPPLY BLOCK DIAGRAM
POWER SUPPLY OUTPUT: (A)
BEAD SET
CHECK AC LINE
VOLTAGE 120V OR 220V
NG
OK
CHECK LINE RECTIFIED
&SMOOTHED VOLTAGE
NG
OK
CHECK START C.K.T
R923, R928, D911, D917
OK
CHECK T901 O/P
NG
OK
CHECK IC901
NG
OK
CHECK Q901
VARIABLE OUTPUT: 80V - 160V
(DEPENDING EPENDING UPON H.SYNC FREQUENCY)
(B) CONSTANT OUTPUT: 6.3V, 14.2V, -12V, 60V AND 77V
CHECK F901,
SW901
CHECK BRIDGE
RECTIFIED
CIRCUIT
CHECK
77V,60V,14.2V
6.3V,-12V Circuit
Output
IC901 FAILURE
ABNORMAL VARIABLE OUTPUT
MAKE SURE THAT THE
VARIABLE OUTPUT IS
NOT SHORTED
NG
OK
CHECK THE 60V
NG
OK
IC401 Pin10
(About 11.5V)
NG
OK
IC401 Pin10
(About 11.5V)
NG
CHECK
Q901
22
CHECK IC401
PIN2~6
B+ DRIVER
CHECK D919
Q911
FAILUR
OK