Power Supply Trouble Shooting Chart - Tatung VM5ERDA Service Manual

BEFORE CHECK SW.REG. PLEASE REFER TO THE POWER SUPPLY BLOCK DIAGRAM
POWER SUPPLY OUTPUT: (A)
BEAD SET
CHECK AC LINE
VOLT 120V OR 220V
NG
OK
CHECK LINE RECTIFIED
& SMOOTHED VOLT
NG
OK
CHECK START C.K.T
R923, R924
OK
CHECK T901 O/P
NG
OK
CHECK IC901
NG
OK
CHECK Q901

6-10 POWER SUPPLY TROUBLE SHOOTING CHART

VARIABLE OUTPUT : 88V - 160V
(DEPENDING EPENDING UPON H.SYNC FREQUENCY)
(B) CONSTANT OUTPUT : 6.3V, 15V, -12V, 75V
CHECK F901, SW901
CHECK BRIDGE
RECTIFIED CIRCUIT
CHECK 75V, -12V, 15V
6.3V CIRCUIT
IC901 FAILURE
ABNORMAL VARIABLE OUTPUT
MAKE SURE THAT
THE VARIABLE
OUTPUT IS NOT SHORTED
YES
CHECK 75V LINE
OK
CHECK Q911
OK
CHECK IC401 #29
(IT SHALL BE 11.5V)
NG
CHECK Q901
NO
CHECK IC401
H-OSC SEE ITEM 1
NG
CHECK D919
NG
Q911 FAILURE
OK