Output problem with G5 Infinium amp

I have a G5 Infinium amp with an output issue. There is very little output to the speaker. While on the distortion channel, the amp sounds like it’s “shorting out” like getting a staticky signal with hardly any sound at all. This is while strumming the guitar while turning up the gain and volume. Absolutely no sound will come out of the clean channel. 


I checked my cables, speaker, guitar and the tubes. The tubes appear to be working fine and it sounds fine with headphones plugged in.


Pretty disappointed. I’ve had this amp for four years, but it has very little playing time on it. It might have gotten used 1 or 2 hours a month. It even sat for a while as I healed after an accident that cut part of my finger off.