28
8. Protection Block (HA-3 Chassis)
Standby light blinks three times – TV Shutdown
Circuit – Referring to Figure 8-6, the maximum voltage the +135V line can rise to from the D board is +140V
before the TV is shut down. IC6505 and Q6522 sense the danger and apply a voltage through D6537 when this
limit is reached. This voltage triggers latch Q6530/Q6532 that shuts off the TV (RY6501 = OFF).
Testing - To verify the trip condition, on the D board, monitor CN6506/pin 7. If this voltage rises above 0.6Vdc, the
problem is on the D board, either in the sensing circuit (IC6505/Q6522) or the secondary power supply (IC6501).
To determine if the problem is in the sensing circuit or the secondary power supply you will need a peak reading
DVM. Monitor the +135Vdc at CN5509/pin 9 (D Bd). Note the reading at power ON. If this voltage is too high, go
to the regulating circuit that is found in the Secondary Power Supply chapter of this book. Suspect the Control
IC6503 and perhaps static/lightning damage to PH6502. If the voltage peaks at a normal 135Vdc, the problem is
in the IC6505/Q6522 sensing circuit.
Standby light blinks four times – TV Shutdown
Refer to Figure 8-7 for this circuit and testing.
Circuit - A vertical failure because of the output IC or secondary power supply (both on the D board) will cause the
Y/C Jungle, CRT Drive IC3101 (A board) to send emergency serial data to Main Micro IC001 (B board). IC001
turns the TV OFF by dropping the AC relay drive voltage (IC001/pin 69 goes LOW).
Testing - At power on 15v and -15V to the vertical output, IC5004/pins 2 and 4, before you suspect the
vertical IC5004 itself or discontinuity in the vertical deflection yoke path (plug/socket).
IC5004
V OUT
STR9372
IC001
MAIN MICRO
M306V2MF
31
26
IC3101
Y/C CRT DRIVE
CXA2150AQ
25
24
52 53
1
7
2
4
35
5
+15V
-15V
R5046
1.8
?
FROM
SEC P.S
(D BD.)
R055
S DATA
R069
STBY LED
AC RELAY
(B BD.)
S CLK
CN002/
CN3022
+
- V DRIVE
V PROTECT
CN3174/
CN5503
CN3103/
CN5505
R5599
10k
V
DY
D BD.
3 4
B BD.
A BD.
B19
A20
7
50
61
9/6/01
17TVP12 1335
FIGURE 7-7 - SHUTDOWN - 4X INDICATION
1Vp-p
Summary of Contents for KD-34XBR2 - 34" Hdtv Fd Trinitron Wega
Page 77: ...74 RA 5A Chassis Board Layout ...
Page 108: ...APPENDIX ...
