I have a Kenwood KR-7600 receiver driving a pair of Paradigm SE3 Mk2 speakers. Connected to it are a Pioneer PL-12D and an Oppo DV-981HD.
Recently the right channel has been dropping out. It seems to happen with all sources, including the radio, and I've double and triple checked all my cables and external connections. I've also switched the speakers around and also connected a pair of Boston Acoustics I have. It seems to be something in the receiver itself.
When the right channel drops out, it doesn't cut out completely - it's still outputting but at a very low volume. Eventually the sound will come back to the right channel at normal volume. There will also be some loud crackling or static before and sometimes during the loss in volume. The right channel only drops off for a few minutes at a time before coming back, but it's obviously very annoying.
I've taken a few steps to troubleshoot it. I've tried all three sets of speaker connections, and in each case it's always the right channel that cuts out. As I mentioned, it seems to happen with any source. I've replaced speaker cables, tried a different pair of speakers, tried different RCA cables, and tried all of the receiver's inputs. (The turntable and DVD player play fine when connected to a different receiver.)
I opened up the KR-7600 to take a look. The interior is generally pretty clean with a bit of dust. I blew out as much of the dust as I could with compressed air. I saw a good amount of oxidation around the power supply board. I sprayed it with Deoxit and did my best to clean it up. As far as I could tell, the amp board looked OK, and the caps generally look OK (no residue, shrinking, etc.).
The Deoxit seems to have helped - the drop outs seem a bit less frequent (maybe 3-4 times per hour listening session) and don't last long (maybe 5-7 minutes at a stretch). I plan to open it up again and give it a more thorough cleaning and another dose of Deoxit. I'm guessing that it's oxidation and/or dirty contacts, but could it be something else?
