Samantha K Cary , NC March 28, 2015 My built in microwave was sparking when used After googling this problem and realizing a built in microwave/oven would be at least 1500 dollars to repair, I decided to try to replace the wave guide cover. This is where the sparks seemed to be coming from. Taking the old one out was easy, it just popped out using a knife. Within seconds of putting the new one in, I was able to verify this was the problem with the sparking. So an easy fix with a $6 part! Read More... 3 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: Less than 15 minutes