CD-PC1881V
– 42 –
• Playback can only be performed when a disc is
loaded.
Is HF waveform normal (see the Fig. 42-2, 3)?
Check the tracking system.
Is the Focus servo active? (Can you hear it working?)
Check the laser diode driver.
Check the area around IC1(16) - (21) (focus servo circuit).
No
Yes
Yes
Yes
Does the DRF signal change from "L" to "H"?
No
Yes
If the disc is not turning, the DRF
should not change to "H".
Level is abnormal.
No
Yes
Waveform is unstable.
Check the spin system.
Yes
Check the periphery of
IC1 pins 41 and 42.
Check the spin system.
Figure 42-3
Figure 42-2
Waveform in case of
normal play-back
HF
1.0V/DIV
0.5
µ
sec/DIV(DC)
IC1
(When playing
back the disc)
41
3
2
1
4
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
No
Yes
No
• The CD operating keys work.
Check the Focus - HF system.
Playback can be performed without a disc.
Focus search OK
Does the pick-up move up and down twice?
Does the output waveform of IC1(16)(FD) match that shown in
Fig. 42-1?
Check the IC1(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT)
and (53)CE.
Check the area around IC3-CNP2.
Yes
Yes
Figure 42-1
Focus search is
performed two
times when play
operation is done
without disc.
0.5s
0.50 V
IC1 16 FD
2
1
0.5s
0.50 V
IC1 7 TE
