Randall M Scottsdale , AZ February 05, 2016 Appliance: Kenmore Microwave Oven 40185043010 Kenmore Microwave 40185043010: Microwave buzzing loudly when heating. How to replace Microwave High Voltage Transformer. Researched on the interwebs & found likely solution to be transformer replacement. Ordered transformer, received transformer quickly and installed with no problems. Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes