SHARP CD-C831W
Service Manual

CD-C831W
� Playback can only be performed when a disc is loaded.
Is the Focus servo active? (Can you hear it working?) Yes Yes Does the DRF signal change from "L" to "H"? Yes Yes Is HF waveform normal (see the Fig.37-1, 2)? Yes Check the tracking system. Waveform is unstable.
0.5s 1.00 V IC1 16 FD 0.5s 10.0 V IC2 13 CLV+ 0.5s 10.0 V IC1 54 DRF 0.5s 2.00 V IC1 7 TE 2 1 3 4

No

Check the laser diode driver. Check the area around IC1(16) - (21) (focus servo circuit).

No

If the disc is not turning, the DRF should not change to "H".

Check the spin system.

No

Level is abnormal. Yes

Check the periphery of IC1 pins 41 and 42.

Check the spin system.
Waveform in case of normal play-back

HF 1.0V/DIV 0.5µsec/DIV(DC) IC1 41 (When playing back the disc)

Figure 37-1 � Check the tracking system.

Figure 37-2

Check waveform of IC1 pin 7 (TE). The waveform shown in Fig. 37-3 appears, and nodisc state appears soon. Tracking servo is inoperative. Yes Check the periphery of IC 1 pin 8 to pin 15, and IC 3 to CNP2.

Yes

Play is possible in TEST mode.

Yes

The unit will be initialized in Normal mode,but it will not Yes playback.

Normal jump is impeded, and the program top Yes cannot be reached.

Check the periphery of IC 1 pin 14.

Data cannot be read.

Yes

Check the VCO-PLL system.

5ms 1.00 V IC1 7 TE

4

5 ms 5.0 V IC1 54 DRF

3

Figure 37-3 � 37 �