Charles M Aiken , SC February 28, 2015 Appliance: Whirlpool Countertop Microwave 2.0 Cu. Ft. UMC5200BAB06 Whirlpool Microwave Umc5200bab06 / : Bad overheat therm. How to replace Microwave Thermostat. Easy replacement after filing two flats on the you can't get the back off screws. 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes