87
20. RA-5A Chassis Protection Block
1. AC Input OVP – D6016 and Q6010 monitor the DC voltage from bridge rectifier D6015 that corresponds to the
AC input voltage. If the AC input reaches a trip voltage of 165Vac, Q6010 turns on opto isolator PH6004. PH6004/
pin 3 outputs a HIGH that turns on latch Q6105/Q6119. This two-transistor latch grounds out the AC relay drive
voltage at CN6101/pin 4 to prevent the AC relay from turning ON so the TV shuts down.
2. +15Vdc OVP - The 15Vdc line from the secondary power supply (IC6001) on the G board is monitored by
Q6101 and zener D6121. If the 15V line rises to 20.6Vdc, Q6101 turns on latch Q6105/Q6119. This latch
removes the AC relay voltage and the TV shuts down from the excessive voltage. The cause for exc15V
is poor or no regulation in the secondary power supply, or a loss of load. The major load for the 15 line is the
circuitry on the D board.
Sec P.S.
G Bd.
D Board
y
Vertical Output IC8003
y
12V Regulator IC8004
+15V
CN8022/
CN8013
T6003
STANDBY
P.S
2
3
4
1
R6119
Q6119
Q6105
4
5
C26
D6015
AC IN
CN6001
R6112
100
AC RELAY
RY6001
D6001
BRIDGE
RECT.
STBY 5V
Q6120
D6111
C6141
10
R6195
47k
R6133
1k
C6140
Q6101
P
+15V (SEC P.S.)
D6122
D6125
D6126
5.6V
R6134
1k
15V OVP
22V
OCP (SEC P.S.)
+22V
R6111
100
AC IN
OVP
STANDBY 5V
SOURCE
R6060
2.2k
R6064
2.2k
D6017
PH6004
R6132
D6121
20V
R6065
R6067
D6016
12V
C6065
CN6101/
CN3016
CN3020/
CN001
D3009
HP DET. (Q3061)
VIDEO PROCESSOR
IC3006/34
MAIN MICRO
IC001/69
G BD.
A BD.
B BD.
N
N
P
+
27TVP12 1344
Q6010
OVP
+19V
19V
OCP
(SEC P.S.)
FIGURE 20-4 - SHUTDOWN - NO INDICATION - RA-5 CHASSIS
Summary of Contents for KD-34XBR2 - 34" Hdtv Fd Trinitron Wega
Page 77: ...74 RA 5A Chassis Board Layout ...
Page 108: ...APPENDIX ...