Peavey Series 400B / XR-600 Audio Issue

[sgtph3n1x]

I'm losing my mind trying to figure this out! This mixer belongs to my father and up to about 4 months ago (whenever this issue occurred) it was in regular use, mostly light use, playing music, guitar, mic, etc. not at a very loud volume. But the problem is for one the light for COMPRESSION is no longer illuminated, but as long as you have ZERO like completely no lows the audio is clear, once you turn the lows up it sounds distorted almost like a radio trying to tune into a channel on a turn dial. and the lows clip really hard. At first I thought maybe it dirty switches, so I cleaned every one with contact cleaner, that helped with the scratching on the volumes, but it still is clipping, distorted audio, I am sure something is faulty but I have no idea where to even start, I am not really familiar with these amps. and I cannot find a place to get a serviced within 150 miles of my location.

Any help is greatly appreciated!

[colliedogboy1]

Have you tried using your mixer with different speakers?

[sgtph3n1x]

Yes, I have, I've tried 6 different speakers, all the same thing. I even used a set of powered speakers on the, (Main, Monitor, and Effects) Outputs and the problem still persists. I am sure it has a bad circuit somewhere, but I have no idea where to begin, though I did find some corrosion on a transistor and resistor on the board, but I am unaware if that would cause this issue.