As I recall, nearly every component on the circuit boards was replaced with new. These repairs were done by McIntosh engineers using McIntosh parts. The sole purpose of the Clinics was Proof of Performance, where the original specs were guaranteed. The story is that
the original clinic was implemented to repair an issue in the early C20. In mine, they were chasing a distortion anomaly, and showed me the handful of replaced components at the time. I brought the C20 in without a complaint just for the testing which I'd been availing myself of for years at their invitation. If they were happy, I was happy. Would it help if I recorded it playing music with my cell phone and posted it to YouTube for you?