Sharp MD-C2 Service Manual page 68

MD-C2
• When turntable fails to move.
When the mechanism is operating, is the following voltage
found on pin 96 on ICF01?
CD mechanism up : 0V
Other : 5.0V
Yes
Is L output to IC2 pin 26 for 1 seconds when the DISC SKIP
key is pressed?
Yes
Is 4V output between IC3 pins 36 and 37 during operation
stated above?
Yes
Check the loading motor (MK01) and the loading mechanism.
• When the CD tray fails to open or close.
Is there following voltage input in specific state of ICF01 pin96?
Open state: 0V
Close state: 0V
Intermediate state between open state and close state: 5.0V
Is H output to IC2 pin 24 or 25 for 7 seconds when the OPEN/
CLOSE key is pressed?
Is 4V output between IC3 pins 38 and 39 during operation
stated above?
Check the loading motor (Mk01) and the loading mechanism.
• 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
IC2 pin 58 (RESET).
Check the waveform of SCK, SO (DATA) and SI (COMM).
Check the waveform of IC2 pin 55 (SQOUT),
pin 56 (COIN) and pin 57 (CQCK).
See if the pick-up is in the PICKUP IN SW (SW4) position.
If the items mentioned above are OK, check the main
microcomputer ICF01.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Check the SW2(MECHA UP SW) and the wiring from the
ICF01 pin 94 to the SW2.
No
Check the wiring of IC2 pin 26, IC3 pin 23.
No
Check the periphery of IC3.
No
Check the SW1(OPEN/CLOSE SW) and the wiring from the
ICF01 pin 96 to the SW1.
No
Check the wiring of IC2 pins 24 and 25, IC3 pins 41 and 42.
No
Check the periphery of IC3.
No
– 68 –
OK
IC2 defective.
OK
IC3 defective.
OK
IC2 defective.
OK
IC3 defective.