75
17. RA-5A Protect Circuit Troubleshooting
T6003
STANDBY
P.S
2
3
4
1
R6119
Q6119
Q6105
D6015
AC IN
CN6001
R6112
100
AC RELAY
RY6001
D6001
BRIDGE
RECT.
STBY 5V
Q6120
D6111
C6146
10
R6195
47k
R6133
1k
C6140
Q6101
P
+15V
(SEC P.S.)
D6122
AUDIO
PROTECT
FROM
K BOARD
D6125
D6126
5.6V
R6134
1k
15V OVP
22V
OCP (SEC P.S.)
+22V
R6111 100
AC IN
OVP
STANDBY 5V
SOURCE
R6064 2.2k
D6017
PH6004
R6132
D6121
20V
R6065
R6067
D2016
12V
C6065
CN6101/
CN3016
CN3020/
CN001
MAIN MICRO
IC001/69
N
N
P
4
5
C26
FIGURE 17-2 - SHUTDOWN - NO INDICATION - RA - 5A CHASSIS
+
Q6010
OVP
HV
PROTECT
FROM
D BOARD
19V OCP
(SEC P.S.)
D3009
+19V
HP DET. (Q3061)
VIDEO PROCESSOR
ICIC3006/34
R6060
2.2k
17.2TVP14 1463
7/11/02
G BOARD
A BOARD
B BOARD
Troubleshooting
The first step is to verify a protection event is occurring. Observing the timer LED for flash sequences is a good
place to start. The only diagnostic monitoring circuit that will not shut the unit down is AKB (five flashes). If no
diagnostic indications appear, listen for relay clicking sounds. They provide a good indicator as to what direction
to approach. On a properly operating unit, two relay clicks will occur less that 500ms apart. The timer LED will
flash at one-second intervals until the CRT cathodes return IK pulses and the picture will appear.
No Clicking Of Relays: Look for one-second flashes of the timer LED. If none are present, the standby supply is
not operating or the main CPU IC001 is not operating. If the timer LED flashes at any time, the standby supply
is OK. Suspect problems in the relay drive circuit or the relay RY6001. Verify a high command from IC001, pin
69.
One Relay Click Followed By Another At Least One Second Later: Since the two relay clicks occurred more than
500ms apart, the unit is going into protect mode. The lack of the rapid clicks indicates RY6002 is not engaging.
This is caused by a failure of the relay (which is monitored for protection), or a malfunction in the primary supply.
If RY6002 is OK, refer to Chapter 16 on troubleshooting the primary supply.
Two, Rapid Relay Clicks Followed By a Third Click: This symptom provides two valuable clues: The standby
supply and CPU are operating and the primary supply is starting. It may not be staying on, but it is at least
starting. The unit is going into protect and may or may not display diagnostics indications. Since the self-
diagnostic feature tends to lead you in the next direction, troubleshooting a “no Indication” shutdown will be
covered next.