My EP600 from 10 or so years ago started acting up, the volume would be very low and as I increased the gain knob all of a sudden it would jump to like 110dB. In the end as Shawn mentioned the parts for the old amps are no longer available, but Axiom, could quote you on a newer amp if you call them.

The only thing you could try is unplug it from the wall outlet and let set for a couple of minutes and then try it again, that has saved me on some strange poltergeist activites.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85