CD-C451H (serv.man8). Trouble shooting the compact disc section - Sharp Audio Service Manual (repair manual)

cd-c451h (serv.man8) service manual
Model
CD-C451H (serv.man8)
Pages
4 Few pages! See other manuals at the bottom of the first or last page.
Size
111.62 KB
Type
PDF
Document
Service Manual
Brand
Device
Audio / System / Trouble shooting the compact disc section
File
cd-c451h-sm8.pdf
Date

Read Sharp CD-C451H (serv.man8) Service Manual online

– 45 –
CD-C451H
TROUBLESHOOTING (CD SECTION)
When the CD does not function
When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean
the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check
the following items.
Remove the cabinet and follow the troubleshooting instructions.
"Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens.
Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."
Turn the power off.
Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol.
Do not touch the lens with the bare hand.
  When the turntable fails to stop.
Is from
  5 V till 0V down pulse (approx. 300 ms) input
Check the SW3 and the wiring from the IC201 pin 54 to the
SW3.
No
No
into the IC201 pin 54 when the turntable is rotating?
5V
2.5V
0V
Yes
Check IC2 pin26 Q91 and Q93 and the periphery.
Check the SW2 MECHA UP SW and the wiring from the
IC201 pin 21 to the SW2 MECHA UP SW.
No
Yes
Is there following voltage input on the IC201 pin 54 in the
specific state?
When the CD mechanism is moved up: 0V
In other states: 5V
Yes
Is there following voltage input on the IC201 pin 54 in the
specific state?
In other states: 5V
When the CD mechanism is moved up: 0V
•  When turntable fails to move.
Check the SW2 MECHA UP SW and the wiring from the IC201
pin 54 to the SW2 MECHA UP SW.
Is 4V output from the Q91 emitter during operation stated
above?
Yes
Yes
Check the wiring of IC2 pin 26 and Q93 BASE.
OK
No
No
Is L output from the IC2 pin 26 during SEC when the disc skip
switch is pressed?
Yes
Check turntable motor and turntable mechanism.
Check Q91, Q93 and the periphery.
IC701 defective.
IC2 defective.
CD-C451H
– 46 –
•  When the CD tray fails to open or close.
Is there following voltage input in specific state of IC701 pin 53?
     Open state: 0V
     Close state: 0V
  Intermediate state between open state and close state: 5V
Is H output to IC2 pin 24 or 25 for 7 seconds when the OPEN/
CLOSE key is pressed?IC81 is defective. Replace it.
Is 4V output between IC81 pins 3 and 7 during operation
stated above?
Check the loading motor (M3) and the loading mechanism.
Yes
Yes
Yes
No
No
IC2 defective.
No
Check the periphery of IC81.
IC81 defective.
OK
OK
Check the OPEN CLOSE SW and the wiring from the IC701
pin 53 to the OPEN CLOSE SW.
Check the wiring of the IC2 pins 24 and 25, IC81 pins 1 and 3.
•  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.
Check the waveform of SCK, SO (DATA) and SI (COMM).
Yes
Yes
See if the pick-up is in the PICKUP IN SW position.
If the items mentioned above are OK, check the main
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. 47?
Check the IC1(50)(CLK) line, 4MHz.
Check the microcomputer data on pins (51)(CL), (52)(DAT)
and (53)CE.
Check the area around IC3-CNP2.
Yes
Yes
Figure 46
Focus search is
performed two
times when play
operation is done
without disc.
 0.5s
0.50 V
IC1  16  FD
2
1
 0.5s
0.50 V
IC1   7  TE
– 47 –
CD-C451H
•  Playback can only be performed when a disc is
loaded.
Is HF waveform normal (see the Fig. 47-1, 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).
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".
Level is abnormal.
No
Yes
Waveform is unstable.
Check the spin system.
Yes
Check the periphery of
IC1 pins 41 and 42.
Check the spin system.
Figure 47-2
Figure 47-1
Waveform in case of
normal play-back
HF
1.0V/DIV
0.5
µ
sec/DIV(DC)
(When playing
 back the disc)
3
2
1
4
 0.5s
1.00 V
IC1  16  FD
 0.5s
10.0 V
IC2  13  CLV+
 0.5s
10.0 V
IC1  54  DRF
 0.5s
2.00 V
IC1   7   TE
•  Check the tracking system.
Check waveform of IC1 pin 7 (TE).
Play is possible in
TEST mode.
Although IL is possible,
play is impossible.
Check the periphery
of IC 1 pin 14.
Normal jump is impeded,
and the program top
cannot be reached.
Check the periphery of IC 1
pin 8 to pin 15, and IC 3 to
CNP2.
The waveform shown in Fig.
47-3 appears, and no-disc
state appears soon.
Tracking servo is
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
  5 ms
5.0 V
IC1  54  DRF
Figure 47-3
CD-C451H
– 48 –
Yes
No
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.
Yes
Figure 48
Play operation is performed when disc exits.
Yes
Although HF waveform is normal, TOC data cannot be read.
Yes
Check PDO waveform (Fig. 48).
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.
2
3
 0.5s
1.00 V
IC2   3   PDO
 0.5s
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.
Check IC 601 and POWER AMP IC 901.
Abnomal
Yes
Usually, the number of pulses of flawless disc is 100 pulses/sec
or less.
No
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Here you can read online and download Sharp CD-C451H (serv.man8) Service Manual in PDF. CD-C451H (serv.man8) service manual will guide through the process and help you recover, restore, fix, disassemble and repair Sharp CD-C451H (serv.man8) System. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.