Hi All,
The first thing you want to do with any ailing Peavey amp, be it tube or solid state, is thoroughly clean all the Molex interconnects with something fairly aggressive, like CRC Lectra Motive or QD. After a while, Peaveys develop what my former partner calls "Peaveyitis". which is a general deterioration of the conductivity of these connectors. The symptoms can drive you nuts because they don't make any sense.
So clean all the connectors, Dave, and see where you stand. If you're still having problems, at least we can eliminate Peaveyitis as the source.