Service manual

29
VL-NZ50S/H/E/W/NZ80H
VL-NZ100S/H/E
ADJUSTING THE MIC AMP CIRCUIT
1. EE level check
Measuring instrument Valve voltmeter Test point TL608, TL609
Mode P-ON (CAM) Adjustment rating -8dBs ± 3dB
Test signal 1kHz -54dBs sine wave
Procedure 1) Input 1kHz, -54dBs sine wave into TL2692(INT MIC L) and TL2691(INT MIC R).
2) Make sure that the signal level of TL608 Audio-L out and TL609 Audio-R out is within the standard
limits.
Remark TL607: GND
(Wiring board diagram: AIO Side B)
2. Frequency character check
Measuring instrument Valve voltmeter Test point TL608, TL609
Mode P-ON (CAM) Adjustment rating (1kHz standard) 100Hz: -9dBs ± 3dB
10kHz: -1dBs ± 3dB
Test signal 100Hz, 10kHz -54dBs sine wave
Procedure 1) Input 100Hz, -54dBs sine wave and then 10kHz, -54dBs sine wave into TL2692(INT MIC L) and
TL2691(INT MIC R).
2) At this time make sure that the signal level of TL608 Audio-L out and TL609 Audio-R out is within the
standard limits (1kHz standard).
Remark TL607: GND
TL607
TL2674
C2611
TL2680
SC2601
TL2672
2
TL2671
1
TL2675
TL2673
TL2691
TL2692
1
0
C615
C2610
C610 C609
R615
C613
TL609
R642 R613
R616
R641 R609
C616
TL608
R643
C614
C612
R611
R608
R614
R612 C617
TL606
TL605
C639
C619
R629
C620
R619 R617
618
R623 R625
R624
C624 C622 R627 R620
IC601
C628
R628
C627
6
C634
C629
C631
R631
R630
C633
R632
C636
C637
C625
TL2644
2
6
TL2
6
T
L
C642
TL2691(INT MIC R)
EE level check
Frequency character check
TL607(GND)
EE level check
Frequency character check
TL608
EE level check
Frequency character check
TL609
EE level check
Frequency character check
TL2692(INT MIC L)
EE level check
Frequency character check