Anyone have this kind of problem with their amp?

I own a Classe CAP-101 integrated amp that I bought used about 10+ years ago.  Recently, it's developed a problem where the right output channel doesn't operate.  Sometimes, the amp works just fine.  But at other times, the right channel won't operate when I power up.  At still other times, there's no issue when I power up, but the right channel will stop working after a variable period of time, sometimes ten minutes and sometimes thirty or even more.  Occasionally but not frequently, after the channel has stopped working, it will resume working after a while, continue to work for a time but then may revert to not working.  When the channel stops working, turning the amp off and restarting it, and/or unplugging and replugging it, does not restore operability.  I've checked and re-checked my connections (bare wire) without any effect  

It's not my other equipment, because I've inserted another integrated without any issue.

I've taken it to a repair shop but the tech couldn't replicate the problem, so he couldn't diagnose it.

In the past, when I've contacted Classe customer support by email about a previous issue or with a question, I've never even gotten a reply.

Any thoughts/advice?  Thanks in advance.

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I did mention the possibility of a bad solder joint, hours before others, just as an fyi. I do read all the posts in a thread, to get an idea of what has been mentioned. I do not need any credit, however, I am just saying.......and, to throw the piece out, is ludicrous.
Bring it to a good tech.  Have him spray the circuit board with a spray made for identifying where the cold soldered joint(s) are.  Glen Grue of Classe told me they had bad batches of circuit boards on the CAP 101 and CAP150.   It is an easy and cheap fix.  Don’t throw out, it could be given to someone just starting out after it is fixed. 
If you are in the NYC area I am in Northern New Jersey and would be happy to take a look at it and I can repair it.  You can also ship the unit if you would like to.

Happy Listening.