I checked all the latch switches ohm readings and the wires for connection as you suggested. That did not work. So I started suspecting the smartboard was the problem as the only buttons that worked for the oven were the clear/off and clock buttons. I removed the screws on the side of the button panel and swung it down. About mid-way down the panel are three connector plugs in a row. I immediately noticed that the two on the inside were cocked off the pins very slightly. I reseated the connector and powered it up and the oven works once again! These plugs on the smartboard are difficult to see when the panel is in place. I suspect that when I pulled the microwave out part-way to get to the fuse and caps, I must have pulled the connector wires thus some of the pins were not in contact. So your suggestion was not the answer, but it was worth checking. Thanks.