27
8. Protection Block (HA-3 Chassis)
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 su200V to the RGB Output ICs (C board).
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.
IC001
MAIN MICRO
M306V2MF
LATCH
Q3170-3
OCP Q6520
Q6521
Q6524
IC6505
OVP-140V,
Q6522
AC RELAY
RY6501
IC6501
SECONDARY
P.S,
Q6506-7
T6501
LATCH
Q6530,
Q6532
7
8
A26
STBY
LED
AC RELAY
Q6527
(D BD.)
R018
MAIN RELAY
CN001/
CN3020
120V
AC
D6530
R6526
Q6527
AC RELAY
IC001-
MICRO
(A BD.)
D6537
D6501
CN6506/
CN3171
D6513
R6598
R5013 2.2 OHMS
135V TO
H.DRIVE
H.OUT
CN6504/
CN3170
B BD.
R6593
A BD.
D BD.
45
44
A25
C25
OVP
OCP
2
9/4/01
16TVP12 1334
FIGURE 8-6 - SHUTDOWN - 2X, 3X, INDICATION
PRI PRE 15V
FROM
PRIM P.S.
(A BD.)
5V
0V
0V
Summary of Contents for KD-34XBR2 - 34" Hdtv Fd Trinitron Wega
Page 77: ...74 RA 5A Chassis Board Layout ...
Page 108: ...APPENDIX ...
