Sony KDP-57XBR2 Training Manual page 77

The above protection circuits have dedicated communications line with IC001. The 135V OCP/OVP, Low B and
H Stop have direct connections. V Stop and AKB notify IC001 by way of the video process IC3006, which
announces the event via the data bus line. The remaining lines have no communication ties with the main CPU
IC001. They are:
1. AC In OVP: The unregulated B+ in the standby supply primary is monitored by Q6010 and will turn on
PH6004 to activate the protect latch. This is illustrated in Figure 16-1 in Chapter 16...
2. Audio Protect: The speaker lines are monitored for DC component by Q2608, Q2609 and Q2610 on the
K board.
3. 15V OVP: Monitored by Q6101 and D6121 as shown in Figure 17-2.
4. 22V OCP: Excessive current on or loss of +22V also monitored by Q6101 and D6126.
5. 19V OCP: This voltage is generated by the secondary supply and monitored by Q6101 via D6122
6. HV Protect: The HV circuit is monitored for excessive HV or current by IC8006 and IC8007 on the D
board. Troubleshooting this circuit will be covered in Chapter 18.
These monitoring circuits will cause the unit to go into protective shutdown by generating a high signal to the
latch circuit without diagnostic indicators. It has been found that failures in any of the protect circuits can cause
protection event indications in the diagnostics mode. As an example: A HV shutdown will sometimes register an
AKB error. It is a good idea not to rely heavily on the diagnostics but to use it as a guide.
G BOARD
+135V
3X
OCP
AC IN
0X
OVP
15V
0X
OVP
22V
0X
OCP
POWER
LATCH
19V
OCP
AUDIO
PROTECT
HV
PROTECT
AC
RELAY
POWER
ON/OFF
6X
C24
SUB
6.5V
8
OVP
0.02V
OCP
0.1V
7
0.1V
6
CN6101/
+135V
CN3016
OCP
OFF
2X
0.2V
5
4.6V
4
FIGURE 17-1 - PROTECTION BLOCK - RA-5A CHASSIS
17. RA-5A Protect Circuit Troubleshooting
B BD.
IC001
MAIN MICRO
S DATA
A25 C25 C26 B19
CN001/
CN3020
OVP
IC3006
OCP
VIDEO
PROCESSOR
74
STANDBY
LED
(HA BD.)
CB BOARD
S CLK
CG BOARD
A20
CN013/
CN3022
CN3011/
CN3703
9 2
IK
CR BOARD
5X
7
CN3005/
CN8004
6
CN3007/
CN8006
A BOARD D BOARD
17.1TVP14 1464
B IK
2
G IK
2
R IK
V LOSS
4X
7X
H.PULSES
6/24/02