On Tuesday, March 20, 2018 at 4:05:27 PM UTC-4, John-Del wrote:

Many years ago I saw just one DPST protection relay go bad, but it would cause a noisy output or intermittent crackles as the volume was raised as one set of contacts were pitted.

But otherwise I'd say if one side is good, it's most likely not the relay as Dave pointed out. The best you can hope for is that it quits entirely. Nothing is easier than tracing a mute audio channel when there's a working one right along side of it, and nothing is worse than chasing an intermittent audio channel when it's working..

The first test will be that wooden peg on the relay. Agreed that the quiet failure does not lead to the relay first thing.

Peter Wieck
Melrose Park, PA