Check the Focus
-
HF svstem.
1
Playback can be performed without a disc.
I
I-
Yes
Focus search OK
No
Does the output waveform of ICi(lG)(FD) match that shown in
Fig.
15-i?
1
No
Check the area around IC5CNP2.
i
Check the
IC1(50)(CLK)
line,
4MHz.
Check the microcomputer data on pins
(51)(CL),
(52)(DAT)
and
(53)CE.
0.5s
0.50
v
Cl
@
FD
Focus search
is performed
two times
when play
operation is
done without
disc.
0%
0.50
v
ICl
@TD
Figure 15-l
Check the laser diode driver.
Yes
Check the area around
ICl(l6)
-
(21) (focus servo circuit).
Does the DRF signal change fr
Yes
No
If the disc is not turning, the DRF
should not change to
“H”.
Check the spin system.
*~
Is HF waveform normal (see th
i
Yes
Check the periphery-of
ICl pins 41 and 42.
4
Check the tracking system.
Waveform is unstable. Check the spin system.
HF
O.lV/DIV
O.Susec/DIV(DC)
(When playing
back the disc)
Figure 15-2
0.5s
1
.oo
v
ICl
@
FD
0.5s
Waveform in
case of normal
play-back
Figure
15-3
-*
,
-15-