Ok, I'm going to post my own fix. The problem turned out to be a polarity problem, but with a twist. After nothing else worked, I began to wonder if something out of the ordinary might be going on. First I tested the house wiring and according to two different polarity testers everything was correct. So I wondered if I reversed the polarity going into the cook top would it fix the problem? To test my theory I used a short heavy duty extension cord I had made up with those removable ends like you see in the electrical department at Lowes or Home Depot. I simply reversed the hot and neutral wires on the female end of the cord. And yes, my tester indicated this condition. I then plugged the cook top into the cord instead of the wall outlet where it had been. I now works perfectly, so I'm assuming that somewhere in the electrical circuit the polarity is reversed from the way it should be. When I get time to pull the whole thing out again I'll just bet I'll find that the polarity of factory installed cord is incorrect, and by "correcting" the polarity with the extension cord that's why it works now.