This is a good quality scan of the service manual which includes an assembly diagram, block diagram, schematic, and parts list. Exactly what is needed to repair my KR-V55R receiver.
Text excerpt from page 22 (click to view)
QT-CD180H/QT-CD180W
� Focus failure.
Does the optical pickup move up and down when the disc is removed ? Yes Check as stated in item "FOCUS SERVO SAWTOOTH WAVE FAILURE".
No
Is the following waveform output at the pin 62 (FEI) of IC802 when the disc is set ? Yes
pin 62 (FEI)
No
Check the periphery of IC801 and BI801/CNS801. Is it normal ? Yes
The optical pickup is faulty.
pin 86 (FOO) pin 63 (SBAD)
Is the waveform shown above input at the pin 63 (SBAD) of IC802 ? Yes
No
Check the pattern between pin 13 of IC801 and pin 63 of IC802. Check the periphery of IC801 and BI801/CNS801.
IC801 is faulty.
� Focus servo sawtooth wave failure.
Is sawtooh wave output to the pin 66 (FOO) of IC802 ? Yes IC802 is faulty.
No
1.5~2.5sec
Is +8.1V applied to the pins 21 and 22 (VCC) of IC803 ? No Yes
Check the PWB pattern of IC803.
Is sawtooth wave obtained between pins 17 and 18 of IC803 ? Yes
No
Check the PWB pattern of IC803.
1.5~2.5sec
Is sawtooth wave obtained between pins 3 and 4 of BI801/ CNS801 ? (as shown above) Yes
Check the PWB pattern between BI801/CNS801 and IC803. No
BI801/CNS801 connection failure or optical pickup failure.