Do-It-Yourself Story

Determined that smell was coming from microwave by smelling the oven. The smell intensified when the oven was in operation. The smell was strongest where air exits the oven. I opened up the oven and inspected all the electronics and wiring. I found charring on one connector of the smoke and flame detector. The crimped lug was badly melted and charred, and the tab on the sensor was loose. I replaced the crimped on the connector and the sensor with new parts, cutting off the charred length of wire. I reassembled the oven and tested it. It works well and no longer smells of burning electronics.