Whirlpool Microwave MT4078SPB4 Troubleshooting and Repair Help

We’ve put together a list of symptoms for Whirlpool Microwave model MT4078SPB4 below. The top three symptoms for MT4078SPB4 are "Won't start", "Tray won't turn", and "No heat". Click on your symptom to see what causes it and how to fix it. With step by step instructions, repair info, and how-to videos, you’ll see just how easy it is to fix your broken MT4078SPB4 Whirlpool Microwave.