CD-PC672
– 44 –
• 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
Is H output to IC2 pin 24 or 25 for 7 seconds when the OPEN/
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.
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.
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.
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. 44?
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 44
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
