Sharp CD-C250X BK Service Manual page 15

Check the Focus - HF svstem.
Does the output waveform of ICi(lG)(FD) match that shown in
Fig. 15-i?
Check the IC1(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT) and
Does the DRF signal change fr
Is HF waveform normal (see th
Check the tracking system.
HF
(When playing
back the disc)
Figure 15-2
Yes
No
Yes
Yes
Yes
Focus search OK
Check the area around IC5CNP2.
Check the laser diode driver.
Check the area around ICl(l6) - (21) (focus servo circuit).
If the disc is not turning, the DRF
No
should not change to " H" .
Waveform is unstable.
Focus search
is performed
two times
when play
operation is
disc.
Figure 15-l
Check the spin system.
Check the periphery-of
Check the spin system.
Waveform in
case of normal
play-back
Figure 15-3