TROUBLESHOOTING
(CD
SECTION)
The
laser
does
not
go
pn,,
I
When
the
CD
does
not
function
..__
___---___.
-__
pa
disc, turn on the power, set the FUNCTION switch to CD, and check the
voltage
of
CNPBBf.~/
The laser does not go on”.
Check the item of “The spin motor’s CLV
servo
is defective”.
Is the output of pin 3 (HF)
,;
TP751
flat I”
test
mode
4?
When the pickup
moves
to a track
using the UP/DOWN button in test
mode 5, is there audio output?
Is the pickup returned to the inner
The pickup
in
swatch
is defective (ON)
Is the pickup in switch set to
OFF?
OFF
ON
Check the The pickup in
peripheral circuits switch is defective.
of the control
microcomputer.
Check the item of “Track searching is impossible”.
Does the
disc
play back several ten
seconds even after starling playback?
Check the item of “The slide servo does not function”.
No
not
functla
Check the PWB
p&rns
from pin
1
of
CNP881
to
CNP852.
T
- PWB patterns from pin
1
of CNP8.31 to pin
24(Vcc)
of
IC750.1
.___
If 0340
iS
not short-circuited,
IC750
1s
defective.
Check
the
PWB pattern from
IC750.
~___
IC750
is defective.
~~---____
-23-
----.
k the LCD
PWB of CD. (Check the LD ON terminal of
pin
9 of IC97f.)
~-_
Check the
+5
V line of pin
1
of
CNPBBI.
I
S
there
+5
V at the a890 collector?
NO
Check between pin 17 of
CNP851B
and
Q890
base. If OK, 0890 is defective.
1
Yes
___~
Is there
+5
V at pin 5 of
CNP700?
k
The PWB pattern between 0890 and pin 5 of
CNP700
is damaged.
-1
/Yes
---
-~-
--
1
Check the CNP700 and Flexible PWB. If they are normal. the pickup is defective.
-A
mcus.
”
When the disc is
removed, is the
Check the item of
7he
saw-tooth wave for focus servo does
pickup
mowng
up and down?
-
Is the focus gain
adfusting
VR751
sst
to the minimum position?
Y??S
Readjust the focus gain.
1
No
waveform input to pin
40(FE
OUT) of
IC750?
Yes
IC750
is defective.
Is the waveform shown at right input
-b/%Gis
at pin
7(HFOKI
of
IC750?
defective.
-
1
Yes
IC750
is defective.
1
(FpE’%T)
-
Y8S
Is a
saw-toofh
wave generating at pin
LOUT)
of
lC7;
Does the saw-tooth
wave
look like the
)N”Llowing
wavefortn?
Check the R779 and 6767 (pins 23
~~~~~ctiue,
and 22 of
IC750).
If OK,
IC750
is
Yes
Yes.
(The
saw-tooth wave
oscillates
to the positive side once.)
/
:
Check the peripheral circuits of pin
35(FSR
IN) of
IC750.
If OK,
lC750
is defective.
I
S
the
saw-tooth wave being input to
pin
8 of
IC700
(same waveform as
Is the saw-tooth wave generating
between
pins
3 and 6 of
IC700
(same
Check the peripheral parts of
IC700
and the power line. If OK,
IC700
IS
defective.
Is the saw-tooth
wave
generating
between pins 2 and 3 of CNP700
(same waveform as shown above)?
The
CNPPOO
and flexible PWB are connected improperly or
the
pickup
isdetectiy,j
~-~_____
FpwB
pattern
i
dN:aged
/
”
-24-
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