Rick D Westville , IN May 08, 2017 Appliance: KitchenAid Microwave Oven 1.8 Cubic Foot KCMS185JSS5 Kitchenaid Microwave Kcms185jss5: Loud while heating. How to replace Microwave High Voltage Transformer. Checked Magnetron, capacitor, and diode. All checked ok. Magnetron was very low resistance across connections and infinite to ground. Cap checked out at 1uF and diode was checked with a 9V battery and checked out ok with a 3V voltage drop. Ran microwave with cover off and noise seemed to be coming from the high voltage transformer. Replaced transformer. All good. 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes