At 2020-08-29 Virtual Fixit Clinic DLX (560) Lawrence Berkeley National Lab (LBNL) we’re scheduled to see Tai-Ran’s Kenwood Receiver:
Audio Receiver Kenwood KR-3090 2010 or earlier Random loud popping noise. I isolated it to one channel. It appears to get worse after it’s on for a period of time. Yes, I have read many forum discussions about it, located the service manual, opened up the receiver, did some cleaning and testing. Need to pinpoint the exact capacitor or other component that has gone bad. The noise is independent of the volume, the speaker, and the source. It only comes from the right channel.
Tai-Ran provided a .pdf of the service manual which is attached.