SHARP CDBK280V
Manual de Servicio

CD-BK260V/CD-BK2700V/CD-BK280V
(2) Tracking system check. Check the TE waveform at pin 18 on IC1.
If the waveform shown in Figure 47-1 appears and soon after NO DISC appears ? No "Initialization" is possible, but play is not possible ? No Yes The tracking servo is not activated. Check the peripheral circuits at pins 18 and 19 on IC1, pin 23 on IC2, and CNS1A/B.

Yes

A normal jump operation cannot be completed or the beginning of the track cannot be found. Check the around pin 23 on IC2.

"Initialization" is not possible.

Data cannot be read. Check the VCO-PLL system.
Stopped CH1=10 V DC 10:1
T

CH2=1 V DC 10:1

100 ms/div (100 ms/div) NORM:100 kS/s

TE
2

T 1

DRF

=Filter= Smoothing : ON BW : FULL

=Offset= CH1 : 0.0 V CH2 : 0.00 V CH3 : 0.00 V CH4 : 0.00 V

=Record Length= Main : 100 K Zoom : 2K

=Trigger= Mode : NORMAL Type : EDGE CH1 Delay : 2.924 ms Hold off : 0.2 µs

Figure 47-1 (3) Spin system check.
Press the OPEN/CLOSE switch without inserting a disc, and then try starting the play operation.

1. The turntable rotates a little ? (Waveform drawing 47-2) Yes No

The spin driver circuit is OK.

2. The turntable doesn't rotate.

Check around pin 25 on IC2, pins 15 and 16 on IC3, and CNS3A/B.
Stopped
CH1=200 mV DC 10:1
T

CH2=500 mV DC 10:1

1999/04/07 09:51:15 500 ms/div (500 ms/div) NORM:20 kS/s

T

FDO
2

1

SPDO

=Filter= Smoothing : ON BW : FULL

=Offset= CH1 : 0.000 V CH2 : 0.000 V CH3 : 0.00 V CH4 : 0.00 V

=Record Length= Main : 100 K Zoom : 2K

=Trigger= Mode : NORMAL Type : EDGE CH2 Delay : 2.924 ms Hold off : 0.2 µs

Figure 47-2

� 47 �