kinda a newbie, but i have built a few effects from kits and such.

I just aquired an old Gallien Krueger ML250 from my dad. the input jack was broken and I replaced it with no problems. The issue Im having is the output jack on one side is maybe half the volume of the other side. the circuit board look ok with no burns at any of the componet sites. it will drive a 2x12 on one side well. I have a multimeter, a good soldering iron, and some knowledge. where do I start? Pix will follow if anyone can help.

Thanx all