The problem here is either going to be the magnetron, High voltage capacitor, High voltage diode or the door switch. This is not a good DIY fix because factory test equipment will be needed to accurately diagnose the problem plus the unit stores lethal voltage even when unplugged.I recommend you take the unit down and take it to a experienced workshop to have it fixed. The cost would be anywhere between $150 - $250, Bearing in mind that most new units cost around $229 you may want to look for a new unit.After the warning given if you decide you want to fix this yourself and have a multi meter and amp meter I would be happy to assist you further :)
I would like to earn your highest rating, if you are not totally satisfied with my answer please hit the continue button.
If I have answered your questions to your satisfaction please feel free to come back at any time after rating me "Excellent service" for additional questions you may have at no further charge :)Sometimes I will have to give bad news, Please try to find it in yourself to rate me for the service not the bad news.Thanks!Mike.
I figured we were going to go shopping for a new one. You didn't give me "bad" news. Thank you for confirming our outcome. Have a good day!