I have a GE microwave, model JVM6175SF1SS. Pretty standard builder grade model. Recently it just stopped heating. When I turn it on, the timer and light turn on, but that's it. No fan, no turntable, and no heating. I thought the magnetron might be busted, but would that affect the turntable and fan? I checked the door switches, they seem to be fine. What could be the issue with it? I am selling my house and would like to have one less thing to be broken.