93
23. RA-6 Protect Circuit Troubleshooting
28
31
43
44
45
43
72
24
IC309
Y/C
JUNGLE
26
25
Q5003,
Q5004
LATCH
IC704
MAIN u
COM
MAIN
RELAY
D5014
D5007
AUDIO
PROTECT
STBY
UNREG
7.5V
RY6002
Q5001
Q5002
Q5005
D5001
OVP
D5022
Q714
SCLK
SDAT
H PROTECT
V PROTECT
IK
5V LP
135V OCP
135V OVP
+15V LP
+22V LP
6V OVP
HV PROTECT
D BOARD
-19V LVP
+19V LVP
FIGURE 23-1 - PROTECT CIRCUITS RA-6 CHASSIS
23.1TVP14 1472
6/12/02
34
25
58
AUDIO:
DC voltage has been detected on the speaker lines. This is usually caused by audio output IC708. The
audio circuits are located on the A board.
WDT:
A communications error has occurred. The main CPU is unable to communicate with the Y/C jungle IC.
The timer LED blinks continuously at one-second intervals and as soon as 101 of them occur, a failure is registered.
The above protection circuits have dedicated communications, directly or indirectly, with the main micro controller,
IC704, located on the A board. The 135V OCP/OVP, Low B, H Stop, HV and AUDIO lines have direct connections.
V Stop and AKB notify IC709 by way of the video process IC309, which announces the event via the data bus
line. The remaining protect circuits have no communication ties with the main CPU IC709, but will also generate
six blinks of the timer LED. They are:
1. Audio -19V LVP monitored by D5026
2. -15V LVP monitored by D5023
3. +15V, AU +19V, and +22V LVP monitored by Q5007 and D5083
4. Reg 6V OVP monitored by D5019
5. Standby unregulated B+ monitored by D5001
6. Unregulated B+ for low or excessive level monitored by V Sense at pin 1 of IC6003.