Sharp CD-BA250 Service Manual page 41

(2) Tracking system check
Check the TE waveform at pin 15 on IC1.
If the waveform shown in Figure 41-1 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 41-2)
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=10V
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=200mV
DC 10:1
T
FDO
2
SPDO
1
=Filter=
Smoothing : ON
BW : FULL
– 41 –
CD-BA250/CD-BA2600
T
CH2=1V
DC 10:1
=Offset= =Record Length=
CH1 : 0.0V Main : 100K Mode : NORMAL
CH2 : 0.00V Zoom : 2K Type : EDGE CH1
CH3 : 0.00V Delay :
Hold off :
CH4 : 0.00V
Figure 41-1
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
CH3 : 0.00V Delay :
CH4 : 0.00V Hold off :
Figure 41-2
100ms/div
(100ms/div)
NORM:100kS/s
=Trigger=
2.924ms
0.2 s
500ms/div
(500ms/div)
NORM:20kS/s
2.924ms
0.2 s