Disassembly - Pioneer VSX-LX70 Service Manual

1

7. DISASSEMBLY

Note : Even if the unit shown in the photos and illustrations in this manual may differ from your product, the procedures
described here are common.
A
1. Before the Power Amp Block is removed
Before the Power Amp Block is removed, discharge C4209 and C4210 on the TRANS 2-1 Assy, as indicated below.
If you don't, the IC protectors (IC4261 and IC4262) on the VH TR Assy may be open, and DC voltage may be generated at the power
amplifier output, which will result in "AMP ERR."
[Procedure]
1
Unplug the AC code.
2
Discharge C4209 and C4210 on the TRANS 2-1 Assy.
Note: For discharging, use a load of 100Ω, 3W or more, to protect the IC protectors. Do NOT discharge instantly by short-circuiting.
B
3
Check that the voltage between the electrodes of each C4209 and C4210 is 1V or less.
4
Mount the Power Amp Block.
C
D
E
F
80
1
2
U
TRANS 2-1 ASSY
+67V
IC4201
MAIN
TRANS
AEK7021
SECONDARY
7A
VHa 23
VLa 24
25
VLa 26
VHa
27
IC4202
AEK7021 7A
-67V
2
3
R4205 R4207
4.7k 3.3k
(1W) D4203-D4204
(1/2W)
D4213-D4214:UDZS***
LMF
LMF
*
/KU
AWX8913
D4203 10(B)
VH+
D4204 9R1(B)
D4213,
12(B)
D4214
Q4201
RN1901
Q4201
RN1901
RT3T22M RT3T22M
Q4202 Q4202
D4215
13(B)
D4216
13(B)
Q4203 Q4203
RT3T22M RT3T22M
V-12A
+58V
R4206 R4208
3.3k
4.7k
(1/2W)
(1W)
LMF
LMF
J4201 D20PDY0610E
1 2 3 4 5 6
VH TR ASSY
C4209
C4210
TRANS 2-1 ASSY
VSX-LX70
3
4
GAMP
CN4202
52151-0510
VH+
VH-
POWER AMP IN
NECK6
ASSY
NECK8
V-12A
VH-
-58V
4