52
VSX-LX52
1
2
3
4
A
B
C
D
E
F
1
2
3
4
7. DISASSEMBLY
Preparations Before Performing Diagnosis of the POWER AMP Assy
Before performing diagnosis of the PO
W
ER AMP Assy, it is necessary to discharge C5721 and C5722 on the board.
(See the photo below.)
If you don't, the protectors (P5001 and P5002) on the board may be open, and DC voltage may be generated at the power
amplifier output, which will result in "AMP ERR."
(1) Unplug the power cord.
(2) Discharge C5721 and C5722 by connecting J270 and pin 1 of D4701, as well as J273 and pin 4 of D4701.
Note:
For discharging, use a load of 100
Ω
, 3
W
or more, to protect the IC protectors. Do
N
OT discharge instantly by
short-circuiting.
(3) Check that the voltage between the electrodes of each C5721 and C5722 is 1
V
or less.
[Procedures]
PO
W
ER AMP Assy
C5722
C5721
D4701
D4701
J270
pin 1
+
pin 4
≠
J273
DIODE Assy
P5002
P5001