Problem with integrated amp

After many years I took my Advantage S100 ( now Bladelius) out of my cabinet and put it into my hifi rack again.
The first day everything was fine and I remembered how good it sounded, but the next day the right channel started to drop out.
After putting it on standby, then turning it on again, it would sound fine again.
Sometimes it can play fine for hours, then other times it will loose the sound in the right speaker more often, sometimes it comes back to both speakers, but most often I have to put the amp in standby, then turn it on again.
As I am writing this I just notice that this also happens to my left speaker!!!?
I have checked all the connections, and they seam fine.
Hope for some input.
Thanks.

 

Did you clean all of the pots?

 

Pots?! Sorry English is not my first language, can you explain for me please?
My amp is fully balanced design
I am using the XLR inputs from my Primare Dac 30

 

The "control" knobs, like the volume and balance

 

It's a close design, can not see anything behind the front, I think it's a semi digital volume and balance knobs

 

I don't know-- it may time to call the dealer / service center and have them sort it out

 

Yeah, have sent Bladelius group a few mails, they replied the first time with basic questions, but never heard back from them, don't think they have any costumer relations people there!
Have today sent a mail to the Danish importer, hope he can help.
I live in Faroe Islands so not so easy to get this sorted