Sharp CD-PC651H (serv.man4) Service Manual ▷ View online
– 49 –
CD-PC671H/651H
• When the turntable fails to stop.
Is from
5 V till 2.5V down pulse (approx. 300 ms)
Check the SWM3 and the wiring from the IC701 pin 21 to the
SWM3.
SWM3.
No
No
input into the IC701 pin 21 when the turntable is rotating?
5V
2.5V
0V
Yes
Check IC2 pin26 the periphery.
Check the MECHA UP SW and the wiring from the IC701 pin
21 to the MECHA UP SW.
21 to the MECHA UP SW.
No
Yes
Is there following voltage input on the IC701 pin 21 in the
specific state?
When the CD mechanism is moved up: 0V
specific state?
When the CD mechanism is moved up: 0V
In other states: 4.3V
Yes
Is there following voltage input on the IC701 pin 21 in the
specific state?
specific state?
In other states: 4.3V
When the CD mechanism is moved up: 0V
• When turntable fails to move.
Check the MECHA UP SW and the wiring from the IC701 pin
21 to the MECHA UP SW.
21 to the MECHA UP SW.
Yes
Yes
Check the wiring of IC2 pin 26.
OK
No
Is L output from the IC2 pin 26 during SEC when the disc skip
switch is pressed?
switch is pressed?
Check turntable motor and turntable mechanism.
IC701 defective.
IC2 defective.
CD-PC671H/651H
– 50 –
• When the CD tray fails to open or close.
Is there following voltage input in specific state of IC701 pin 19?
Open state: 0V
Close state: 0V
Intermediate state between open state and close state: 4.3V
Intermediate state between open state and close state: 4.3V
Is H output to IC2 pin 24 or 25 for 7 seconds when the OPEN/
CLOSE key is pressed?IC91 is defective. Replace it.
CLOSE key is pressed?IC91 is defective. Replace it.
Check the loading motor (M1) and the loading mechanism.
Yes
Yes
No
No
IC2 defective.
OK
Check the OPEN CLOSE SW and the wiring from the IC701
pin 19 to the OPEN CLOSE SW.
pin 19 to the OPEN CLOSE SW.
Check the wiring of the IC2 pins 24 and 25.
• The CD function will not work.
The CD operating keys don't work.
Check the CD, DSP, power supply, and 16.93 MHz clock, and
reset terminal.
reset terminal.
Check the waveform of SCK, SO (DATA) and SI (COMM).
Yes
Yes
See if the pick-up is in thePICKUP IN SW position.
If the items mentioned above are OK, check the main
microcomputer IC701.
microcomputer IC701.
Yes
Yes
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. 50?
Fig. 50?
Check the IC1(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT)
and (53)CE.
Check the microcomputer data on pins (51)(CL), (52)(DAT)
and (53)CE.
Check the area around IC3-CNP2.
Yes
Yes
Figure 50
Focus search is
performed two
times when play
operation is done
without disc.
performed two
times when play
operation is done
without disc.
0.5s
0.50 V
IC1 16 FD
0.50 V
IC1 16 FD
2
1
0.5s
0.50 V
IC1 7 TE
0.50 V
IC1 7 TE
– 51 –
CD-PC671H/651H
• Playback can only be performed when a disc is
loaded.
Is HF waveform normal (see the Fig.51-1, 2)?
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).
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".
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.
IC1 pins 41 and 42.
Check the spin system.
Figure 51-2
Figure 51-1
Waveform in case of
normal play-back
normal play-back
HF
1.0V/DIV
0.5
1.0V/DIV
0.5
µ
sec/DIV(DC)
IC1
(When playing
back the disc)
(When playing
back the disc)
41
3
2
1
1
4
0.5s
1.00 V
IC1 16 FD
1.00 V
IC1 16 FD
0.5s
10.0 V
IC2 13 CLV+
10.0 V
IC2 13 CLV+
0.5s
10.0 V
IC1 54 DRF
10.0 V
IC1 54 DRF
0.5s
2.00 V
IC1 7 TE
2.00 V
IC1 7 TE
• Check the tracking system.
Check waveform of IC1 pin 7 (TE).
Play is possible in
TEST mode.
TEST mode.
The unit will be initialized
in normal mode, but it will
not play back.
in normal mode, but it will
not play back.
Check the periphery
of IC 1 pin 14.
of IC 1 pin 14.
Normal jump is impeded,
and the program top
cannot be reached.
and the program top
cannot be reached.
Check the periphery of IC 1
pin 8 to pin 15, and IC 3 to
CNP2.
pin 8 to pin 15, and IC 3 to
CNP2.
The waveform shown in
Fig.51-3 appears, and no-
disc state appears soon.
Fig.51-3 appears, and no-
disc state appears soon.
Tracking servo is
inoperative.
inoperative.
Yes
Yes
Yes
Yes
Yes
Data cannot be read.
Check the VCO-PLL system.
Yes
3
4
5ms
1.00 V
IC1 7 TE
1.00 V
IC1 7 TE
5 ms
5.0 V
IC1 54 DRF
5.0 V
IC1 54 DRF
Figure 51-3
CD-PC671H/651H
– 52 –
• Checking the spin system.
Yes
No
Play operation is performed without disc.
The turntable rotates a little.
The turntable fails to rotate or rotates at high speed.
Yes
The spin driver circuit is normal.
Check the periphery of IC1 pins 23 to 27, pin 39, and pin 40, IC2
pin 12 and pin 13, IC3 to CNP3.
pin 12 and pin 13, IC3 to CNP3.
Yes
• Checking the VCO-PLL system
Figure 52
Play operation is performed when disc exits.
Yes
Although HF waveform is normal, TOC data cannot be read.
Yes
Check PDO waveform (Fig. 52).
Abnormal
Check the IC1 pins 43 and 44, IC2 pins 3, 5, 7, 10, and 11.
Stop --> Play
As VCO freque-
ncy is locked at
4.32 M Hz, voltage
of PDO rises and
stabilizes.
ncy is locked at
4.32 M Hz, voltage
of PDO rises and
stabilizes.
2
3
0.5s
1.00 V
IC2 3 PDO
1.00 V
IC2 3 PDO
0.5s
1.00 V
IC2 16 FD
1.00 V
IC2 16 FD
• Although HF waveform is normal and the time
indication is normal, no sound is emitted.
Check IC 2 pin 48 (EFLG).
Check IC2 pins 37, 40.
Yes
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
or less.
No
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