Tom, you mentioned having another supply. Hook that one up for a while to see if the problem appears again. If so, its not the same supply. Then swap out each jumper switch and tuner in the same way. I don't know anything about the tentec tuner. I have an MFJ 989 with a big roller inductor. Every few years I have to clean the roller and the shaft it sits on. Lots of contact cleaner for the job. H T Kaufman MSW LCSW Adaptive Technology Instructor