I have a Maytag over-the-range microwave (model MMV4205AA) that suddenly malfunctioned while cooking. The humming noise normally present while cooking got at least twice as loud and sounded more like a pronounced vibration. Also, after about 20 seconds of loud humming, the microwave had a strong ozone/hot smell so I stopped it. The auxillary functions like exhaust fan, light, timer, turntable, etc all function normally. The cook function produces the loud humming and smell. The microwave is approximately 18 months old, and has a grounded 20A dedicated circuit feeding it. Any ideas how to proceed? Where do I start troubleshooting? Thanks.
An expert who has achieved level 3 by getting 1000 points
Sounds like you just fried your magnetron. Normally when they go bad, they make a very loud noise like what you described. The smell concerns me because you may have ruined the waveguide as well. If the magnetron burns through the protective painted surface of the waveguide, the waveguide is ruined. In most microwave ovens this means replacing the entire unit because the waveguide is not replaceable. Putting a new magnetron in a damaged waveguide will result in the same arcing and eventual failure. In addition to the magnetron, the following components are part of the same high voltage network: HV Transformer HV Diode HV Capacitor Magnetron Thermal Cut-Out Any one of these components could have also been damaged. I DO NOT recommend taking any voltage measurements inside the HV network. Potentials of over 4000 volts can be reached and make it very dangerous for the do-it-yourselfer. Taking resistance readings with the unit unplugged is strongly encouraged. If you decide to pursue a repair, inspect the magnetron tip and inside of the waveguide first. If the magnetron is melted and/or there are burn marks inside the waveguide, a new microwave may be a in order. This actually may be a better option than an expensive repair. I hope you find this advice helpful.
Posted on Jul 31, 2007
Apr 08, 2016 | GE Profile Spacemaker Over-the-Range...
Jan 16, 2016 | Kenmore 8504 Over-The-Range Microwave 1.7...
Dec 25, 2012 | Maytag MMV6180WS Over the Range Microwaves
Aug 31, 2012 | Maytag Appliances Over-the-Range Microwave...
Apr 22, 2012 | Maytag Appliances Over-the-Range Microwave...
Apr 24, 2010 | Maytag 2.0 Cu. Ft. Over-the-Range...
Dec 17, 2017 | Maytag MMV4205 Microwave Oven
Jan 12, 2008 | Maytag MMV5156AAS Microwave Oven
Dec 30, 2007 | Microwave Ovens
Mar 20, 2007 | Kenmore 62622 Microwave Oven
Sep 26, 2014 | Whirlpool GH4155XP Microwave Oven
1,260 people viewed this question
Usually answered in minutes!
×