Sharp CD-MPS440W Service Manual page 52

CD-MPS440W
(2) Tracking system check.
Check the TE waveform at pin 16 on IC401.
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.
Check the peripheral circuits at pins 15, 16 and 23 on IC401,
Yes
and FC401.
A normal jump operation cannot be completed or the beginning
of the track cannot be found.
Yes
Check the around pin 23 on IC401.
Data cannot be read. Check the VCO-PLL (Pin26~30 on IC401)
system.
Stopped
CH1=10 V
DC 10:1
TE
2
=Filter=
Smoothing : ON CH1 :
BW : FULL
CH2 :
CH3 :
CH4 :
The spin driver circuit is OK.
Yes
Check around pin 25 on IC401, pins 10 and 11 on IC402, and
CNW402.
Stopped
CH1=200 mV
DC 10:1
T
FDO
2
SPDO
1
=Filter=
Smoothing : ON CH1 :
BW : FULL
CH2 :
CH3 :
CH4 :
7 – 3
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