Sharp CD-C5H Service Manual page 52

CD-C5H,CP-C5H
• The CD operation keys work.
Check the FOCUS-HF system.
Playback can be performed without a disc.
Does the pickup move up and down two twice?
Does the output waveform of IC1 pin 16 (FD) match that
shown in Figure 52-1?
Check 4 MHz of IC1 pin 50 (CLK) line and the microcomputer
data of pin 51 (CL), pin 52 (DAT) and pin 53 (CE).
• Playback can only be performed when disc is
loaded.
Is the Focus servo active? (Can you hear it working?)
Does the DRF signal of IC1 pin 54 change from "L" to "H"?
Is HF waveform normal (see the Figure 52-2, Figure52-3.)?
Check the tracking system.
HF
1.0V/DIV
0.5µsec/DIV(DC)
(When playing
back the disc)
Figure 52-2
Yes
Yes
Yes
Yes
Yes
Yes
Focus search OK
No
Check the area around IC3 to CNP2.
No
0.5s
0.50 V
IC1 16 FD
0.5s
0.50 V
IC1 7 TE
Check the laser diode driver.
No
Check the area around IC1 pin 16 to pin 21 (focus servo
circuit).
If the disc is not turning,
No
the DRF should not
change to "H".
Level is abnormal
No
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
– 52 –
Focus search is
performed two
times when play
operation is done
without disc.
1
2
Figure 52-1
Check the spindle system.
Yes
Check the periphery of
Yes
IC1 pin 41 and pin 42.
Check the spindle system.
Yes
Waveform in case of
normal play-back
2
1
3
4
Figure 52-3