Sharp CD-XP700 Service Manual page 44

CD-XP700/CD-XP7700
(2) Tracking system check.
Check the TE waveform at pin 15 on IC1.
If the waveform shown in Figure 44-1 appears and soon after
NO DISC appears ?
No
"Initialization" is possible, but play is not possible ?
No
"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 44-2)
No
2. The turntable doesn't rotate.
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Yes
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.
Yes
– 44 –
The tracking servo is not activated.
Check the peripheral circuits at pins 14, 15 and 20 on IC1, and
CNS1A/B.
T
Stopped
CH1=10 V CH2=1 V
DC 10:1 DC 10:1
TE
2
DRF
T
1
=Filter= =Offset= =Record Length=
Smoothing : ON CH1 : 0.0 V Main :
BW : FULL
CH2 : 0.00 V Zoom :
CH3 : 0.00 V
CH4 : 0.00 V
Figure 44-1
The spin driver circuit is OK.
Check around pin 22 on IC1, pins 15 and 16 on IC2, and CNS3A/B.
T
Stopped
CH1=200 mV CH2=500 mV
DC 10:1 DC 10:1
T
FDO
2
SPDO
1
=Filter= =Offset= =Record Length=
Smoothing : ON CH1 : 0.000 V Main :
BW : FULL CH2 : 0.000 V Zoom :
CH3 : 0.00 V
CH4 : 0.00 V
Figure 44-2
100 ms/div
(100 ms/div)
NORM:100 kS/s
=Trigger=
100 K Mode : NORMAL
2 K Type : EDGE CH1
Delay : 2.924 ms
0.2 µs
Hold off :
1999/04/07 09:51:15
500 ms/div
(500 ms/div)
NORM:20 kS/s
=Trigger=
100 K Mode : NORMAL
2 K Type : EDGE CH2
Delay : 2.924 ms
0.2 µs
Hold off :