PMA 980 with ADD

I have a PMA 980 integrated amp which I love. In in the past few years, it has developed electronics ADD. That is, the input selector and less often the speaker selector occasionally start jumping around for no apparent reason. It is set to, say, CD. I will listen for anywhere between 2 minutes and 2 hours, then the selector starts jumping around - click, click, click - between Aux, Tuner, CD, Phono, etc. etc. I can somewhat relieve the problem my rotating the knob around a bit, then back to CD. Sometimes that works for an hour; sometimes it works for a minute. Again, it does not happen every time, and I cannot see any pattern to the error. I took it to a local repair shop and they ran it for 2 days and said they never saw the problem; can't diagnose, if they can't see the error... like so many car problems. They suggested maybe ambient IR was hitting the remote sensor, so I covered it with electrical tape... no improvement. Has anyone seen this same problem? If the error is in the switch itself, can I get a new one? I truly appreciate any/all assistance
I just re-read my post and, in addition to a number of typos, I realized I neglected to state the make: Denon. Sorry. Maybe that was obvious... but then again.

I sure hope someone can help. I would love to keep using this amp for another 15 years!
Have the same problem here with same model. Needs new selector switch which is no longer available from Denon. An aftermarket non remote switch can be installed for about $175.00. I found by just leaving it on 24/7 solved the problem for the most part and stopped using the remote.

Later replaced with a Denon PMA 757, older unit better build quality and no gremlins. No remote though. My advice if need remote find a Denon PMA 2000r.