Thomas C N. Huntingdon , PA July 20, 2015 Appliance: KitchenAid Microwave Oven 1.5 Cubic Foot KCMS1555SSS1 Kitchenaid Microwave Kcms1555sss1: The microwave suddenly died the display had no indication (e g time lights) of life. How to replace Thrmst - Fix. First checked the breaker at the electrical panel and it wasn't tripped. I then unplugged and opened the microwave to check the fuse for continuity and it was fine. Next I checked the cavity thermistor and it was open. Upon further investigation I noticed the cavity thermistor was slightly deformed as well. After ensuring the internal capacitor was fully discharged, I check the rest of the microwave over for possible additional component failures. Everything else was found to be satisfactory, so I found the correct replacement cavity thermistor part on AppliancePartsPros.com and placed my order. After receiving the new cavity thermistor I checked the continuity to ensure it was operational then I installed it into my microwave and tested the microwave's operation. As soon as I plugged it in I noticed the display was functioning again. Then I placed a cup of water in the microwave to further test it's operation. The microwave is back up and running! Although I am trained in electronics I found the following YouTube video very helpful: https://www.youtube.com/watch?v=t1tdj3OnlXU Good Luck! Do-It-Yourself Rating: Repair Time Estimate: 2+ hours