Sharp MD-X7H, Руководство по обслуживанию

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MD-X8H
– 74 –
• Check the tracking system.
Data cannot be read.
Check the waveform of IC1 pin 7 (TE).
The waveform shown in Figure 74-1
appears, and no disc state appears soon.
Yes
Check the periphery of IC1 pin 8 to pin
15, and IC5 to CNP2.
Tracking servo is inoperative.
Check the VCO-PLL system.
Yes
Yes
Playback is possible in TEST mode.
Yes
Normal jump is
impeded, and the
program top cannot
be reached.
Playback is impossible
although initialization is
possible.
Yes Yes
Check the periphery
of IC1 pin 14.
Figure 74-1
3
4
5ms
1.00 V
IC1 7 TE
5 ms
5.0 V
IC1 54 DRF
• Check the spindle system
Yes
Yes
Play operation is performed without disc.
The turntable rotates a little.
The turntable fails to rotate or rotates at high speed.
The spindle driver is normal.
No
• Checking the VCO-PLL system.
Play operation is performed when disc exists.
Yes
Although the HF waveform is normal, TOC data cannot be
read.
No
Check the periphery of IC1 pin 23 to pin 27, pin 39, pin 40, IC2 pin
12, pin 13, from IC5 to CNP3.
No
Check the PDD waveform of IC2 pin 3. (Figure 74-2)
Check the IC1 pin 43, pin 44, IC2 pin 3, pin 5, pin 7, pin 10, and
pin 11.
Abnormal
Figure 74-2
2
3
0.5s
1.00 V
IC2 3 PDO
0.5s
1.00 V
IC2 16 FD
Stop -- > Play
As VCO freque-
ncy is locked at
4.32 MHz, voltage
of PDD rises and
stabili- zes.