Sharp CD-C602 Service Manual page 31

• The CD operating keys work.
Check the Focus - HF system.
Playback can be performed without a disc.
Yes
Does the pick-up move up and down twice?
No
Does the output waveform of IC1(16)(FD) match that shown in
Fig. 31-1?
No
Check the IC1(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT)
and (53)CE.
• Playback can only be performed when a disc is
loaded.
Is the Focus servo active? (Can you hear it working?)
Yes
Does the DRF signal change from "L" to "H"?
Yes
Is HF waveform normal (see the Fig. 31-2, Fig. 31-3)?
Yes
Check the tracking system.
Figure 31-2
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Yes
Yes
No
No
No
HF
1.0V/DIV
0.5µsec/DIV(DC)
(When playing
back the disc)
– 31 –
Focus search OK
Check the area around IC5-CNP2.
0.5s
0.50 V
IC1 16 FD
0.5s
0.50 V
IC1 7 TE
Figure 31-1
Check the laser diode driver.
Check the area around IC1(16) - (21) (focus servo circuit).
If the disc is not turning, the DRF
should not change to "H".
Level is abnormal.
Waveform is unstable.
0.5s
1.00 V
IC1 16 FD
0.5s
10.0 V
IC2 12 CLV+
0.5s
10.0 V
IC1 54 DRF
0.5s
2.00 V
IC1 7 TE
Figure 31-3
CD-C602,CP-C602
Focus search is
performed two
times when play
operation is done
without disc.
1
2
Check the spin system.
Yes
Check the periphery
Yes
of IC1 pins 41 and 42.
Check the spin system.
Yes
Waveform in
case of normal
playback
2
1
3
4