SHARP SD-EX220H
Service Manual

SD-EX220H

2-2 Tracking system check. Check the TE waveform at pin 15 on IC1.
If the waveform shown in Figure 7-3-1 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 14, 15 and 20 on IC1, and CNS1A/B.

Yes

A normal jump operation cannot be completed or the beginning of the track cannot be found. Check the around pin 20 on IC1.

"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 �s

Figure 7-3-1 2-3 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 Figure 7-3-2) No 2. The turntable doesn't rotate.

The spin driver circuit is OK. Yes

Check around pin 22 on IC1, pins 15 and 16 on IC2, 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 �s

Figure 7-3-2

7�3