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.

An easy place to start is to make sure all the wiring/cable connections are clean and tight. Try pushing/twisting the interconnects/cables when the channel goes silent and see if that makes a difference.    
You have to be careful twisting/turning interconnects while amp is powered up. you can damage components and especially speakers with loud signal serges which can be devastating.

Hello jimcrane. My first time replying to anyone on any issue.

I tinker with audio gear and amps are easiest to fix. Much more info is needed. This will take sometime. When channel cuts out is there a noise at that moment such as a boom, scratch noise? When channel goes quiet is there a noise from the speaker such as a low hum or hissing? When channel goes out stop playing music and listen to both speakers up close. Every amp has a quiet noise when it is idle with no music playing called temperature noise. If both speakers have identical sound the most likely problem is before amp stage and probably in amp input stage. If good channel is normal temperature noise and bad channel is dead quiet it is in final out put stage. I wonder if there is a rely on the end of out put stage with bad contact.

1-Unfortunately you have to install  cheap pair of speakers instead of main speakers (protect them from load bursts), take the cover off and look for relays. Run your amp until bad channel goes quiet. With a plastic rod (break a plastic coat hanger to get a 8 inch or longer rod and slowly press on relays, connectors and boards that can flex looking for bad connection or poor solder joint. Sound might come back and try this process many times to zero in on a component.

2-If it is heat issue with out put transistors going bad you should see discoloration of circuit board at the part that is running over temp. Amp has protection to shut it down when temp is high. That is why power cycling amp does not help. How ever cooling it down might make it come back to normal. That is sign of bad output transistor. 

There are some many ways this can happen that might fill 10 pages. Lets us start with simpler things.