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
There are 4 thermostats (aka TCO = Thermal Cut Out) in the GE JVM1440BH04 The schematic is under the cover in a black envelope to the top left of the unit if you face the door.
Check the fuse first. You can remove the front grate, then the numpad on the right. The fuse is right behind it. It's a 250V 20A Class F fuse.
There are four (4) TCOs or Thermal Cut Out thermostats in this puppy:
1) There is a thermostat behind the button panel to the left, facing down. If blown, it breaks the power coming into the unit and will cause a no power situation.
2) There is another TCO or thermostat near the top lamp, to the left, in a small cavity. That one also breaks power to the unit and will cause a no power situation. It's a 100 C / 0 C thermostat. This was the one that blew on me after I left the stove running (for heating in a black-out) under the microwave.
"Cavity TCO" or "Thermostat" part number 61 on the schematics, part number PS239319
3) There is yet another power-breaking TCO or thermostat in the cavity behind the fan that cools the microwave coils. You have to remove the sheet metal on the right of the microwave to access it. This one also breaks power and will cause a no power situation.
1), 2) and 3) should test out to be 0 Ohms with a resistance meter (Digital Multimeter) if working correctly.
4) There is a thermostat which normally does not let current through it. It is mounted in a vertical position to the back wall behind the front panel on the right. This one is used for the sensor reheat function apparently and will close when the temperature in the microwave reaches approx. 60 C.
4) should have infinite resistance with a resistance meter under normal circumstances.
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.
