Idle Current Adjustment - Pioneer VSX-1128-K Service Manual

1

8.4 IDLE CURRENT ADJUSTMENT

A
When any component parts which are within the red square on the following circuit diagram are replaced, the idle current
adjustment of that channel is required. (Idle current adjustment for another channel is not required.)
However, when any capacitors are replaced, the adjustment is not required.
(The following circuit diagram is for SL channel, but another channel also has same circuit diagram and same adjustment is
required)
B
C408
R428
R427
1K2 1K5
22/50
AGND
C
Measurement
Channel
TP404 pin 1 (+)
FL
TP404 pin 3 (–)
TP402 pin 1 (+)
FR
TP402 pin 3 (–)
TP403 pin 1 (+)
C
TP403 pin 3 (–)
TP401 pin 1 (+)
SL
TP401 pin 3 (–)
TP405 pin 1 (+)
SR
D TP405 pin 3 (–)
TP406 pin 1 (+)
SBL
TP406 pin 3 (–)
TP407 pin 1 (+)
SBR
TP407 pin 3 (–)
• Adjustment points and measurement points.... see fig.1.
K
AMP7 ASSY
SL_VR401 FL_VR404
E
VR401
SL ADJ
VR404
FL ADJ
SL ADJ
TP401
F
SL_TP401
50
1
2
(SL)
R401
1K2
Q401
KTA1024Y
C406
22P-500V
R461 R470
NM NM
C405
R429
NM
33K
Q407 Q408
KSA992F
KSA992F
C409
82P-50V(1608)
R434
- Q412
KTC3206Y
C413 R440
R710
C435
2N2-K 150 270
C525
-
Adjustment
Points Points
VR404
VR402
VR403
VR401
VR405
VR406
VR407
C_VR403
C ADJ
TP403
C ADJ
VR403
FL ADJ
TP404
C(+)
J583
FL_TP404 C_TP403
2
3
C404
47/50(6.3*11)
Q404
2SD2390
R415
100(1)
Q409
KTC3964
!
VR401
1K(B)-V
!
R439
100(1)
Q410
2SB1560
-
1 Turn on the power.
2 Perform aging for one minute.
3 Connect a digital voltmeter to the measurement point.
4 Turn the adjustment VR so that the voltage becomes
in 2.0 mV ± 0.2 mV.
(Condition : No signal and no load)
SR_VR405 FR_VR402
VR402
FR ADJ
SR ADJ
VR405
SR ADJ
TP405
SR(+)
SR_TP405 FR_TP402
Fig.1
VSX-1128-K
3
4
!
TP401
! 1 2 3
R411 150K
D402
R417
270K
1N4148
R423
10K
!
(SL)
!
!
Procedure
SBL_VR406 SBR_VR407
VR406
SBL ADJ
SBR ADJ
VR407
TP402
FR ADJ
SBL ADJ
TP406
SBL_TP406
4
SL
Q403
2N5401S
R412 47K
R416 22K
R419 22K
SIDE A
SBR ADJ
TP407
SBR_TP407