Sharp CD-MPS700 Service Manual page 75

(2) Focus-HF system check.
Check the TE waveform at pin 17 on IC1.
If the waveform shown in Figure 4 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 5)
2. The turntable doesn't rotate.
No
No
No
The tracking servo is not activated.
Yes
Check the peripheral circuits at pins 16, 17 and 22 on IC1, and
FFC1.
A normal jump operation cannot be completed or the beginning
Yes
of the track cannot be found.
Check the around pin 22 on IC1.
Data cannot be read. Check the VCO-PLL (Pin76~80 on IC1)
system.
Stopped
CH1=10 V
DC 10:1
TE
2
DRF
T
1
=Filter=
Smoothing : ON CH1 :
BW : FULL CH2 :
CH3 :
CH4 :
Yes The spin driver circuit is OK.
Check around pin 24 on IC1, pins 3 and 4 on IC2, and CNS3A/
CNS3B.
Stopped
CH1=200 mV
DC 10:1
T
FDO
2
SPDO
1
=Filter=
Smoothing : ON CH1 :
BW : FULL
CH2 :
CH3 :
CH4 :
7 – 3
CD-MPS700
T
CH2=1 V 100 ms/div
DC 10:1 (100 ms/div)
NORM:100 kS/s
=Offset= =Record Length= =Trigger=
0.0 V Main : 100 K Mode : NORMAL
0.00 V Zoom : 2 K Type : EDGE CH1
0.00 V Delay : 2.924 ms
Hold off : 0.2 µs
0.00 V
Figure 4
T
1999/04/07 09:51:15
CH2=500 mV 500 ms/div
DC 10:1 (500 ms/div)
NORM:20 kS/s
=Offset= =Record Length= =Trigger=
0.000 V Main : 100 K Mode : NORMAL
0.000 V Zoom : 2 K Type : EDGE CH2
0.00 V Delay : 2.924 ms
Hold off : 0.2 µs
0.00 V
Figure 5