My Onkyo receiver crackles in the left channel occasionally, and sometimes goes out. When I fiddle with the balance nob, mono sound will come out both speakers, and if I continue to fiddle with it, it will come out stereo properly for awhile. It there a simple cleaing or fix for this?
You can try spraying contact cleaner into all of the controls. If that doesn't work, its time to call in the pros.