Hello friend greetings for what you comment the problem is in the large reley of the electronic board which controls the large transformer of the high voltage insurance is flamed its internal contacts and stayed stuck to know how to disconnect the two wires that feed the large transformer and place a focus on those two wires put the microwave to work or connect it to the power grid if the light turns on without giving any function. Tap this reley if the light goes out. I commented and should be replaced by one of the same characteristics to the original to solve the fault greetings. Atte Hector from Venezuela