I reseated the connectors on the controller board and the oven started working again. It only worked for a day or two. At least I knew I was looking in the right area. A new card is $265 if I bought it locally and $220 + SH if I did mail order. I decided that I would take a chance and look at the controller circuits themselves. I could see nothing particularly wrong with the cards but since I am an electrical engineer and am handy with a soldering iron, I thought that maybe the problem was a bad connection on the circuit card. I spent about an hour just going through all the solder joints and touching them up. everything now works. This fix is not for everyone, but if you have to spend the money for a new controller anyway, and you are proficient with a soldering iron, give it a try.