Sharp CD-C602 Service Manual page 30

CD-C602,CP-C602
• When turntable fails to move.
Is there following voltage input on the IC2 pin 28 in the specific
state?
When the CD mechanism is moved up: 0V
In other states: 4.3V
Yes
Is L output from the IC2 pin 26 during SEC when the disc skip
switch is pressed?
Yes
Is 4V output from the Q91 emitter during operation stated
above?
Yes
Check turntable motor and turntable mechanism.
• When the CD tray fails to open or close.
Is there following voltage input in specific state of IC2 pin 27?
Open state: 0V
Close state: 0V
Intermediate state between open state and close state: 4.3V
Yes
Is H output to IC2 pin 24 or 25 for 7 seconds when the OPEN/
CLOSE button is pressed? IC91 is defective. Replace it.
Yes
Is 4V output between IC91 pins 3 and 7 during operation
stated above?
Yes
Check the loading motor (M3) and the loading mechanism.
• The CD function will not work.
The CD operating buttons don't work.
Yes
Check the CD, DSP, power supply, and 16.93 MHz clock, and
reset terminal.
Yes
Check the waveform of SCK, SO (DATA) and SI (COMM).
Yes
See if the pick-up in the PICKUP IN switch position.
Yes
If the items mentioned above are OK, check the main
microcomputer IC701.
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No
No
No
No
No
No
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Check the MECHA UP switch and the wiring from the IC2 pin
28 to the MECHA UP switch.
Check the wiring of IC2 pin 26 and Q93 pin 2.
IC2 defective.
Check Q91, Q93 and the periphery.
Check the OPEN/CLOSE switch and the wiring from the IC2
pin 27 to the OPEN/CLOSE switch.
Check the wiring of the IC2 pins 24 and 25, IC91 pins 1 and 3.
IC2 defective.
Check the periphery of IC91.
IC91 defective.
OK
OK
OK