Sony KD-34XBR2 Training Manual page 30

Standby light blinks two times – TV Shutdown
There are two +135V OCP monitoring circuits. The first circuit will cause the Standby light to blink two times and
the second will cause the light to blink seven times. Both sensing and output circuits are on the D board but the
indicating circuit is on the B board.
Circuit - Refer to Figure 8-6 for the following circuit and testing procedure. The sensing circuit consists of R6598,
R6591, Q6520, Q6521 and Q6524. It monitors the current on the +135V line from the Secondary Power Supply.
The +135 volt line supply the following loads:
•
Velocity modulation (V) board
•
Horiz Output (Q5030) and PWM (Q5003) stage (D board)
•
The HOT supplies +200V to the RGB Output ICs (C board).
IC6501
SECONDARY
Q6506-7
T6501
R6526
D6530
120V AC RELAY
AC RY6501
AC RELAY
IC001-
MICRO
(A BD.)
LATCH
Q6530,
Q6532
FIGURE 8-6 - SHUTDOWN - 2X, 3X, INDICATION
Testing – You can test the sensing circuit by removing R5013 (disconnects the load) and power up the TV to see
if the standby LED blinks 2X. Since the sensing circuit has a low failure rate, the TV will usually stop the 2X
blinking, indicating the load is at fault. The +135Vdc load goes to the H. Output/PWM stage on the same D board
and the velocity modulation coils on the V board.
To locate the problem, monitor CN6506/pin 8 as you power ON. The normal voltage here is 0Vdc. If the voltage
reaches 1.2V, disconnect the V board and try again. If the CN6506/pin 8 voltage still rises to 1.2V, test the H
Driver transistor Q5028, H Output transistor Q5030 and PWM transistors (Q5003, Q5011) or replace the entire D
board.
The circuit description and simplified schematic of this PWM-H Output section is in the DTV-02 training manual
on page 37.
MAIN RELAY
P.S,
D6513
PRI PRE 15V
FROM
PRIM P.S.
(A BD.)
R6593
IC6505
OVP-140V,
Q6522
Q6527
D6537
D6501
CN6504/
CN3170
R5013 2.2 OHMS
135V TO
R6598
H.DRIVE
H.OUT
OCP Q6520
Q6521
Q6524
CN6506/
CN3171
D BD.
27
8. Protection Block (HA-3 Chassis)
IC001
MAIN MICRO
M306V2MF
45 44
R018
A26 A25 C25
CN001/
2
CN3020
5V
OCP
OVP
LATCH
Q3170-3
0V
7
0V
8
A BD.
16TVP12 1334
STBY
LED
AC RELAY
Q6527
(D BD.)
B BD.
9/4/01