72
16. RA-5A Power Supply Troubleshooting
V
SENSE
1
IC6001
DRIVER
MCZ3001D
16
12
9
8
15
18
14
10
2
PH6002
OPTICAL
ISOLATOR
4
2
IC6101
CONTROL
DM-58
5
4
1
PRIMARY
POWER
SUPPLY
AC
AC
D6530
DC
T6002
PIT-AU
R6041
0.1 OHM
R6013
R6015
Q6507
Q6001
N
Q6002
N
R6022
D6502
R6O70
VC2
VC1
V B
OCP
Q6003
R6033
P
R6035
Q6506
R6052
R6590
N
CH
N
CH
D6104
R6021
FIGURE 16-3 - SECONDARY POWER SUPPLY RA-5A CHASSIS
1
9
12
10
9
11
15
14
8
9
10
13
7
2
4
1
3
R6017
R6014
7
Vcc
R6055
R6073
R6074
R6054
Vcc
NO CONNECTION
VD
FROM
MAIN
SW.
PH6003
R6056
D6107
L6106
135V
SOURCE
C6022
C6028
C6033
C6034
D6116
-19V
+19V
-15V
+15V
-22V
+22V
AUDIO
GROUND
D6105
D6108
D6117
T6001
PIT
STBY
5V
SS
PS101
PS102
PS103
PS104
16.3TVP14 1466
6/13/02
D BOARD
Troubleshooting the Secondary Supply
Once the primary supply has been proven to be operating correctly, the diagnostics checks are similar to servicing
the primary supply. As long as there is confirmation of no problems in the primary circuits, the main AC relay
RY6001 can be jumped and power applied with the variac. AC current and the 135V line voltage must be
monitored closely. By monitoring AC current and the 135V line, the results will designate where to proceed.
AC Current Less Than 1.5A, 135V OK: Loss of ±15V or ±22V supplies has occurred. These lines are monitored
by the protect circuits.
AC Current Less Than 1.5A, 135V line too high: Troubleshoot regulator loop as outlined in primary supply
procedures.
AC Current Exceeds 3A at low AC input: There is a short or excessive dynamic load. Disable secondary lines to
isolate. If secondary lines check OK, suspect leaking coupling capacitors C6033/34 at T6001 or C6022/28 at
T6002, or defective transformers.