Barbara B Lawrence , KS August 11, 2015 Appliance: KitchenAid Microwave Hood Combo KHMS155LBL2 Kitchenaid Microwave Khms155lbl2: My kitchenaid microwave kept turning itself on. How to replace Microcomputer. I replaced the microcomputer - sort of like replacing the motherboard in a computer, It took about 45 minutes but it saved replacing my microwave. Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes