Sharp CD-DD4500 Service Manual page 53

(2) Tracking system check.
Check the TE waveform at pin 15 on IC1.
If the waveform shown in Figure 53-1 appears and soon after
NO DISC appears ?
"Initialization" is possible, but play is not possible ?
"Initialization" is not possible.
(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 53-2)
2. The turntable doesn't rotate.
No
No
No
The tracking servo is not activated.
Yes
Check the peripheral circuits at pins 14, 15 and 20 on IC1, and
CNS1A/B.
A normal jump operation cannot be completed or the beginning of
Yes
the track cannot be found.
Check the around pin 20 on IC1.
Data cannot be read. Check the VCO-PLL system.
Stopped
CH1=10 V
DC 10:1
TE
2
DRF
T
1
=Filter=
Smoothing : ON
BW : FULL
The spin driver circuit is OK.
Yes
Check around pin 22 on IC1, pins 15 and 16 on IC3, and CNS3A/B.
Stopped
CH1=200 mV
DC 10:1
T
FDO
2
SPDO
1
=Filter=
Smoothing : ON
BW : FULL
– 53 –
T
CH2=1 V
DC 10:1
=Offset= =Record Length=
CH1 : 0.0 V Main : 100 K Mode : NORMAL
CH2 : 0.00 V Zoom : 2 K Type : EDGE CH1
CH3 : 0.00 V Delay :
Hold off :
CH4 : 0.00 V
Figure 53-1
T
1999/04/07 09:51:15
CH2=500 mV
DC 10:1
=Offset= =Record Length= =Trigger=
CH1 : 0.000 V Main : 100 K Mode : NORMAL
CH2 : 0.000 V Zoom : 2 K Type : EDGE CH2
CH3 : 0.00 V Delay :
CH4 : 0.00 V Hold off :
Figure 53-2
CD-DD4500
100 ms/div
(100 ms/div)
NORM:100 kS/s
=Trigger=
2.924 ms
0.2 µs
500 ms/div
(500 ms/div)
NORM:20 kS/s
2.924 ms
0.2 µs