Unit Will Not Power Up - Sony KDP-57XBR2 Training Manual

FROM SWITCHING B+
FROM VCC SOURCE
9
D6015/K
FROM IC6003/9
10
E1 OSCILLATOR
12
FROM IC6003/10
11
E2 OSCILLATOR
13
2
D6031
VCC
+12V
9
10
12
11
13
2

Unit Will Not Power Up

Look at the timer LED. If it is blinking once a second, the standby supply is working. The main and inrush current
relays will now become an important tool in deciding where to go next.
No relay clicks heard: There should be two, distinct, rapid clicks heard. If none are heard, troubleshoot the circuit
starting from the relay high command from the CPU through the VCC switch circuitry and even the main relay
itself. Refer to Figure 8-3 to troubleshoot this circuit.
Relay clicks once: If a relay click is heard, it is very important to listen carefully for two rapid clicks. They should
be less the one-half of a second apart. This verifies the inrush current relay is engaging. If only one, and not two,
rapid clicks are heard, the unit will power up for a short period and then the oscillator will stop. The main relay will
still be engaged and there will be no other indicators as to what is wrong. This is the symptom of the inrush relay
protection. Check for a defective relay or loss of 14V supplied by Q6106 on the 16.5V line on the secondary of
T6001. One might think that a failure of the oscillator circuit could cause this symptom but several of the
secondary voltages are monitored by the protect circuits and the relay click sequence will differ as shown next.
It is very important to verify this test as it can lead the technician to the wrong areas.
Two rapid relay clicks: The presence of the two clicks indicates the power supply is oscillating. One item that can
produce the symptom of a dead set is the loss of 12V from IC501 on the A board. This would prevent the
horizontal oscillator from running and may mimic the symptom of a dead unit.
VDD
HO
7
HIN
VB
6
C6020
LIN
VS
5
D6016
SD
LO
1
C6018
VSS
VCC
3
GND
IC6002 C6021
DRIVER
IR2112
VDD
HO
7
HIN
VB
6
LIN
C6032
VS
5
SD
D6025
VSS LO 1
C2029
GND
VCC
3
IC6004
C6037
DRIVER
IR2112
FIGURE 8-5 - CONVERTER
F6002
FB6002
R6025
C6019 D6019
D6022
MTZJ
MTZJ
-20C
-20C
FB6001 R6024
D6021
MTZJ
-20C
D6017
MTZJ
-20C
R6036
FB6004
C6030 D6028
D6030
MTZJ
MTZJ
-20C
-20C
FB6003 R6035
D6021
MTZJ
D6026
-20C
MTZJ
-20C
34
8. RA-4/4A Power Supply Troubleshooting
Q6008
C6026
R6027
C6025 C6022
Q6007
R6026
SWITCHING B+
Q6010
C6023
C6034
R6038
C6033
Q6009
R6026
SWITCHING B+
T6002 PIT
8
10
4
12
2
12
10
11
15
13
14
1
18
3
16
17
8
7
9
T6001 PIT
8.5TVP14 5/22/02