Here's the datasheet:
http://www.ti.com/lit/ds/symlink/pcm55.pdfLooks like a simple R2R ladder/buffer.
Here's the service manual:
https://www.hifiengine.com/manual_libra ... 1500.shtmlIC300 is turning the datastream into 16-bit, uncompressed WAV audio for decoding. Each channel is independent after IC300. If the analogue was bad, one channel would likely be worse than the other.
How's the power supply voltages? Capacitor health (need a recap?) Solder joints, etc?
I'd check for proper alignment. The control/audio recovery chips either work or they don't. If it's aligned, the head itself may be pooched.
Had a B&O CD where everything was good, but bad audio. The laser itself was *really* low on power and only recovered enough data to spin the CD at the right RPM and read the odd music. Otherwise it was done and done
Cheers!