A:Answer I've had the same problem. Microwave was 7 months old when bulb burned out. When unscrewing old bulb, there was a spark and it shorted out a circuit board. We've been waiting a month for the part and it's still not here. Home Depot has the bulbs, but whatever you do, unplug the microwave before removing the bulb. You don't want to go through the same thing we are.