No power to GE microwave JVM1540LM1CS
The ceramic in-line fuse tests ok., and the door switches check out ok. Four thermostats are located within the unit--one is what they used to call the flame arrestor and is located in the top of the unit pointing downward and shows continuity (#AP3994055), one is on a bracket attached to the side of the magnetron and shows no continuity (#AP4344046), one is attached to the bottom panel and shows no continuity (part # is the same as the one attached to the magnetron), and the fourth is attached to the bottom panel adjacent to the one just mentioned--this one shows continuity (#AP3994357). Perhaps I am barking up the wrong tree but I thought that all four of these thermostats should show a continuity, but the two with the same part # are open. Would this be a coincedence, and if open would this shut all power off to the unit, or could it be another issue. any comments would be greatly appreciated---LarryAnswer
On every microwave I have ever worked on the thermostat on the magnetron tube should be closed (continuity) and if not it is bad. I agree it does sound a little odd that the same switch would be open, it sounded so odd that I looked at 5 service manuals (couldn’t find one for your exact model) for similar GE models and they all indicate that the thermostat should be closed. As far as I know it has always been like that unless it is different for your model. I suggest replacing the thermostats and go from there.