Speaker relay - transistor, cap question

[mjz3348]

Amateur question.

I have a Kenwood KR-7600 Receiver. After two years in storage, I powered it up. Worked great for a few days and then the speaker relay will start to cut in and out intermittently. It's most notable when the receiver is warmed up - and then it sort of goes away after an hour run time - although it will still happen. The speaker relay will click - no sound - and then a few seconds later, the relay will click shut again and music resumes.

I checked the circuit driving the DC protection and saw no unusual voltage - although it will jump 200 mv every time the relay opens and shuts. The relay acts first and then I see the voltage change. It seems the amp is fine - but the speaker protection circuit has problems.

There is a transistor which drives the relay. I suspect it's getting bad as well as the electrolytic cap(s).

My question is since the problem is intermittent - is it most likely a transistor problem? If a cap failed - wouldn't the relay just stay open and not go intermittent?