Power Supply Trouble Shooting Chart - Tatung VM9K9DA Service Manual

6-10 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
VOLT 120V OR 220V
NG
OK
CHECK LINE RECTIFIED
& SMOOTHED VOLT
NG
OK
CHECK START C.K.T
D909, Q904, R922, R925
R923,R924
NG
OK
CHECK T901 O/P
NG
OK
CHECK IC901
NG
OK
CHECK Q901
VARIABLE OUTPUT : 60.5V - 145V
(DEPENDING EPENDING UPON H.SYNC FREQUENCY)
(B) CONSTANT OUTPUT : 6.3V, 14.5V, 55V, 80V
CHECK F901, SW901
CHECK BRIDGE
RECTIFIED CIRCUIT
CHECK POWER SAVING
C.K.T(OFF-MODE)
NG
CHECK 80V, 55V, 14.5V 50V
6.3V CIRCUIT
IC901 FAILURE
22
ABNORMAL VARIABLE OUTPUT
MAKE SURE THAT
THE VARIABLE
OUTPUT IS NOT SHORTED
YES
CHECK THE C934
VOLTAGE 55V
OK
CHECK Q911
OK
CHECK Q912, Q914, Q915
CHECK Q901
NO CHECK IC401
PIN 4, 5, 6, B+ DRIVER
NG
CHECK D919
NG
Q911 FAILURE
OK