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. ?
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 41-2)
No
2. The turntable doesn't rotate.
All manuals and user guides at all-guides.com
Yes
Yes
Yes
– 41 –
CD-BA250/CD-BA2600
The tracking servo is not activated.
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
the track cannot be found.
Check the around pin 20 on IC1.
Data cannot be read. Check the VCO-PLL system.
T
Stopped
CH1=10V CH2=1V
DC 10:1 DC 10:1
TE
2
DRF
T
1
=Filter= =Offset= =Record Length=
Smoothing : ON CH1 : 0.0V
BW : FULL
CH2 : 0.00V
CH3 : 0.00V
CH4 : 0.00V
Figure 41-1
The spin driver circuit is OK.
Check around pin 22 on IC1, pins 15 and 16 on IC3, and CNS3A/B.
T
Stopped
CH1=200mV CH2=500mV
DC 10:1 DC 10:1
T
FDO
2
SPDO
1
=Filter= =Offset= =Record Length=
Smoothing : ON CH1 : 0.000V Main :
BW : FULL
CH2 : 0.000V Zoom :
CH3 : 0.00V
CH4 : 0.00V
Figure 41-2
100ms/div
(100ms/div)
NORM:100kS/s
=Trigger=
Main : 100K Mode : NORMAL
Zoom : 2K Type : EDGE CH1
Delay : 2.924ms
Hold off : 0.2µs
1999/04/07 09:51:15
500ms/div
(500ms/div)
NORM:20kS/s
=Trigger=
100K Mode : NORMAL
2K Type : EDGE CH2
Delay : 2.924ms
Hold off : 0.2µs