Sony KD-34XBR2 Training Manual page 29

The following test for the video output ICs is
quick, but dangerous to the technician. In the
next box, you will unplug the TV, then unplug
the C board from the CRT. You must keep
away from the CRT pins, especially at TV
turn ON and OFF. The exposed CRT pins
will have 37kV on them in this test. Plug
the C board back only when the TV is OFF.
Front of TV
D Board
R8051
Q8009
FBT
1
Pin 1 of each connector
begins at this end.
PRESS
POWER ON
BUTTON
TV SHUTS OFF WITHIN 6 SECONDS OF POWER ON
NO STANDBY LED DIAGNOSTIC INDICATION
PH6503/pin 3
CN6503
CN6505
CN6504
8
CN6506
CN6503
10
CN6505
CN6501
1
FIGURE 8-4 - FLOW CHART A
TV SHUTS OFF WITHIN 6 SECONDS OF POWER ON
NO STANDBY LED DIAGNOSTIC INDICATION
7VDC AT
CN4403/2-(A BD.)
(CN6503/2-D BD.)
YES (MOMENTARY)
200V AT
Q8009/BASE & EMITTER
(D BD.)AFTER
PRESSING POWER ON?
YES (MOMENTARY)
LESS THAN 0.3V AT
Q8009/C
(D BD.) AT POWER ON?
YES
MORE THAN 5VDC
(ABL VOLTAGE)
AT FBT T8001/PIN 1
AT POWER ON?
YES
LATCH CIRCUIT DEFECT
AT Q6530,Q6532 (D BD.)
FIGURE 8-5 - FLOW CHART B
With the TV OFF, unplug the C
board from the CRT. Also unplug
the 200V supply to this board by
removing CN9002. Insulate the
board, keep away from the CRT
pins and turn ON the TV. Does
the TV stay ON?
No
Remove the fusible R8051
(D Bd) to stop B+ to HV
converter stage. Turn ON
the TV. Does the TV stay
ON?
No
The problem is in the:
Primary PS (A Bd),
Surge Relay circuit ( D Bd.), or
Latch circuit (D Bd.)
NO
TROUBLESHOOT A BD.'s
PRIMARY POWER SUPPLY
(IC6001)
LESS THAN 3VDC
NO
AT PH6503/PIN 3
(D BD.) AT POWER ON
YES
LATCH Q6503
Q6526,Q6528-9
NO
ARE
SUSPECT (D BD.)
HV
CONVERTER
IS DEFECTIVE
(D BD.)
ABNORMAL FBT
NO ABL VOLTAGE
CHECK FOR
SHORTED VIDEO
OUTPUT IC's OR
SHORTED FBT,
EXCESS HV
26
8. Protection Block (HA-3 Chassis)
Check Video Output
IC9001-3 (C Bd) for
Yes
shorts and Y/C CRT
Drive IC3101 for
constant 9V high at R,
G, or B output (A Bd)
Problem is in the
Yes
HV converter
stage (D Bd.)
Go to
Flow Chart B
25TVP12 8/30/01
REPLACE
SURGE
NO
RELAY
RY6502
AND
PH6503 (D BD.)
22TVP12 1340 9/4/01