So I picked this amp up used -

It powers on - You can only faintly hear sound on the gain channel when turned all the way up.
I checked the speaker - it is good - I checked the wires to the speaker -they are good

I have it apart and nothing is burnt up or loose - fuse is good

I ran the Line out into an interface and the quality of sound through my recording device is good.

I am worried that this is a more severe problem - like the power amp section has crapped out. 

Does anyone have any suggestions? Any help is welcome!