You'd have to contact Absolute Sound Labs to find out if they will work on your particular gear. They only seem to work on a limited amount of non-McIntosh equipment. For example, I asked them if they could look at my Pioneer SX-1250, and they said no.
There is also Savage Audio. They do a lot more than just guitar amps. I stopped in there a while back, and there was a large variety of gear in for service. They said that they'd be happy to work on my SX-1250 (although I haven't actually brought it to them yet.)
https://savageamps.com/repair-restore