?? Yesterday the left channel on a receiver started popping and distorting. Then it dropped out completely. I noticed the bias on the power transistors was gone. I wiggled the trimpot (open type) and the bias and the sound came back, but then it started popping again. I tried WD-40, alcohol, graphite from a pencil... While it improved, it still refuses to make good contact and crackling is still there. Any ideas?
