Pioneer CDXP23S is an old model and has been top useful for me to find this Manual. CD Player is still repaired.
Text excerpt from page 20 (click to view)
KD-SX787
Feed section
Is the voltage output at IC521 pin "40" 5V or 0V? YES Is 4V present at both sides of the feed motor? YES Check the feed motor. NO Is 6V or 2V present at IC561 "4" and "5"? NO Check IC561. NO Is the wiring for IC521 (56)~(64) correct? NO YES Is 3.3V present at IC561 pin "20"? YES Check the vicinity of IC521. YES Check the feed motor connection wiring. NO Check CD 8V and 5V.
Focus section
When the lens is moving: 4V
Does the S-search waveform appear at IC561 pins "8" and "9"?
NO
Check the circuits in the vicinity of IC561 pins "8","9"and"15". YES
YES
Check the pickup and its connections
Spindle section
Is the disk rotated? YES Does the RF signal appear at TP1? YES NO Is 4V present at IC561 pins "6" and "7"? YES Check the spindle motor and its wiring NO NO Is 4V present at IC521 pins "41" ? YES Check the vicinity of IC561. Check IC521 and IC501. NO
Is the RF waveform at TP1 Check the circuits in the distorted? NO vicinity of IC501 "19"~ "24" or the pickup YES Proceed to the Tracking section
Tracking section
When the disc is rotated at first:
YES
Approx. 1.2V Is the tracking error signal output at IC501 "11"?
Check the circuit in the vicinity of IC501 pins "2"~"12".
