At first I tried to use pliers to unscrew the base,very uncomfortable working position,upside down and backwards(the microwave is installed over the range top)very limited space for your body and arms to manuver and you really cant see the base,all of this took place after the breaker was turned off ofcourse,finally figured out that you can drop the entire bottom housing of the microwave by unscrewing 6 screws and the light sockets are easily accessable once you lower it,take out 1 retaining screw ,remove the entire socket and unscrewed the broken base and replaced the bulbs,I said bulbs,there is no sense in having to replace another bulb in who knows how long since only one had burned out but they were both the same age
First, I waste $65 by calling some "REPAIR" service. They showed at home and charge me that just to tell me Second, I researched on the web and ordered a part, which was not the issue. I waste abnother $72 Third, I found Part-Select and got the right answer: the Diode was the problem. Ordered the part form Part-Select and it FIxed it !!!
Note: I did not buy a new microwave because this one is mounted on the wall and it will cost me +$800 just the lowest price.
Loosen screw holding glass cover plate in place over bulb. Glass cover plate will swing down. Unscrew bad bulb, replace with good bulb, reset glass cover and tighten screw.