OK?..manual is complet and helpfull... for repairing such a old and rare boombox like JVC PCM it is necessary...
Text excerpt from page 24 (click to view)
3.2 Troubleshooting 3.2.1 Feed section
Is the voltage output at IC521 pin u 5V or 0V? NO Is the wiring for IC521 (90) ~ (100) correct? YES Is 5V present at IC581 pin 6? YES YES Check the vicinity of IC521. NO Is 6V or 2V present at IC581 Q and R? NO Check IC581. YES Check the feed motor connection wiring. NO Check CD 9V and 5V.
Is 4V present at both sides of the feed motor? YES Check the feed motor.
3.2.2 Focus section
When the lens is moving: NO Check the circuits in the vicinity of IC581 pins H K. YES
Does the S-search waveform appear at IC581 pins H and I?
Check the pickup and its connections.
3.2.3 Spindle section
Is the disk rotated? YES Does the RF signal appear at TP1? YES Is the RF waveform at TP1 distorted? YES Proceed to the Tracking section NO NO Check the circuits in the vicinity of IC501 J O or the pickup Check the spindle motor and its wiring. NO Is 4V present between IC581 pins 1 and 2? NO Is 4V present at IC521 pin x? YES Check the vicinity of IC581. NO Check IC501 and IC521.
3.2.4 Tracking section
When the disc is rotated at first: YES Approx. 1.2V Is the tracking error signal output at TP3? YES Check IC521. Check the circuit in the vicinity of IC501 pins ~ 2C . YES Check the pickup and its connections