Sharp CD-BA1200H Service Manual page 39

(2) Tracking system check
Check the TE waveform at pin 18 on IC1.
If the waveform shown in Figure 39-1 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 39-2)
2. The turntable doesn't rotate.
No
No
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.
Data cannot be read. Check the VCO-PLL system.
Stopped
CH1=10V
DC 10:1
TE
2
DRF
T
1
=Filter=
Smoothing : ON
BW : FULL
Yes
The spin driver circuit is OK.
Check around pin 25 on IC2, pins 15 and 16 on IC3, and CNS3A/B.
Stopped
CH1=200mV
DC 10:1
T
FDO
2
SPDO
1
=Filter=
Smoothing : ON
BW : FULL
– 39 –
CD-BA1200H
T
CH2=1V
DC 10:1
=Offset= =Record Length= =Trigger=
CH1 : 0.0V Main : 100K Mode : NORMAL
CH2 : 0.00V Zoom : 2K Type : EDGE CH1
Delay :
CH3 : 0.00V
CH4 : 0.00V Hold off :
Figure 39-1
T
1999/04/07 09:51:15
CH2=500mV
DC 10:1
=Offset= =Record Length= =Trigger=
CH1 : 0.000V Main : 100K Mode : NORMAL
CH2 : 0.000V Zoom : 2K Type : EDGE CH2
Delay :
CH3 : 0.00V
CH4 : 0.00V Hold off :
Figure 39-2
100ms/div
(100ms/div)
NORM:100kS/s
2.924ms
0.2us
500ms/div
(500ms/div)
NORM:20kS/s
2.924ms
0.2us