Paul J Parkville , MD February 16, 2017 Appliance: Model LG MICROWAVE Thermostate (correct name is a thermister; 1 time over heat and reacts like a fuse) Actual problem was due to a poor connection from the circuit board and HV transformer, over time this poor / loose connection began to arc causing enough heat to physically melt the connector and the contact to the thermistor. the problem was obvious but I still followed procedures to check all the components.*** NOTE*** ALWAYS UNPLUG DEVICE FIRST, WITH MICROVAVES, ALWAYS, ALWAYS, DISCHARGE HV CAPICITOR, IT CAN KILL YOU! just take your time testing components, following your electronic education, I prefer to use expensive equipment to test in my lab but you could just use a decent multimeter I did replace the slow blow fuse, thermistor, a few insulated connectors, and the HV diode just as a precaution as these are easy to replace, and cheep, to insure continued operation.. Read More... 5 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes Tools: Pliers, Screwdrivers