Service manual

33
VL-NZ50U/NZ100U
VL-NZ150U
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
TL268
6
TL2642
TL2690
TL2676
TL2667
R622
R640
TL2646
R621
C642
TL2659
C626
TL2644
R638
C625
C621 C623
R626
IC601
R618
TL606
TL605
R612
R611
R643
C614
C612
C616
R616
R642 R613
R615
C610 C609
C2610
C615
R610
TL2675
TL2673
TL2691
TL2692
R2611
TL2671
R2612
R2614
TL2672
SC2601
R2626
C2611
TL2674
TL607 TL2680
C613
TL609
R641 R609
TL608
R608
R614
C617
C639
C619
R629
C620
R619 R617
R623 R625
R624
C624 C622 R627 R620
C628
R628
C627
C634
C629
C631
R631
R630
C633
R632
C636
C637
TL2643
TL2645
TL2662
TL2687
TL2689
TL2688
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