Microwave MH6140XKQ doesnt want to start

SOURCE: Maytag Rangehood Microwave Loud Humming

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.

William Miller

• 9179 Answers
• Posted on Nov 17, 2007

SOURCE: GH7145XFB-1 not heating properly

Generally, the most common causes of a failure to heat are:

- bad door switches or door switch mounts
- loose connection at the magnetron
- problem or loose conneciton on the control unit circuit board
- bad magnetron or other high voltage part

If you or a friend decide to look into it, we have critical safety information, info on door switch diagnosis and replacement, and disassembly information at our site, linked here on Fixya: http://tinyurl.com/yzjozk

SOURCE: Microwave won't heat/Makes buzzing noise.

The symptoms you are describing are typical of a magnetron that has gone bad. Continuing to attempt to use the oven in its current condition can cause further damage. So, I would recommend not using it. Microwave ovens are considered dangerous and repairs should not be attempted by anyone that is not electronic saavy. The High Voltage Network inside the oven has voltage potentials of 14,000 volts and higher. If you feel this is something you wish to attempt, the Magnetron part number is 1156751 and costs approx. $158. Keep in mind, if the magnetron has been arcing and making a burning smell you may have burned the protective coating that lines the walls of the waveguide. If the waveguide is damaged it is not repairable. I do not know if this is a replaceable item on your model microwave. Double check your warranty information and/or owner's manual. In many cases the magnetron is warranted for several years beyond the limited warranty that comes with most appliances. Post back with comments and let me know if you want me to assist you further. In addition, if you provide me with your EXACT model number (located along the door opening) I can narrow down parts a little better. I know this all sounds discouraging, but I do hope I have been able to help you.

William Miller

• 9179 Answers
• Posted on Jun 16, 2009

SOURCE: Kenmore microwave loud popping noise when start

That sounds like maybe a high voltage wire or component is running too close to the chassis or one of the components connected to it.

Gruesome as it sounds, sometimes a pest can get inside the works and can move wires around or be killed, then its carcass can conduct electricity and cause arcing.

It may instead be a failing high voltage diode.

To find helpful exploded view diagrams and get part numbers, you can just enter your full model number (66562619200) at the Sears parts site.

Here are some links you or someone you know can use (in order given) for test help, but

http://www.gallawa.com/microtech/cap_test.html

http://www.gallawa.com/microtech/diode.html
(if it is NOT shorted or burned looking, it's probably fine)

http://www.gallawa.com/microtech/mag_test.html
(continuity can be good even though mag is bad!)

http://www.gallawa.com/microtech/xformer.html

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

William Miller

• 9179 Answers
• Posted on Jul 05, 2009

SOURCE: whirlpool microwave model #MH1140XMQ-1. I needed

We see (and repair) this a lot. The problem is on the control panel, which we regularly repair nationwide by mail for $39.95 postpaid in about a week or so.

At our Web site, you can get details of our service, plus we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.

Or if you prefer, you can order a new control circuit board for it here for $140.10 plus shipping. (Just enter the model number as MH1140XMQ-1 without the dash).

This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.

The lights can can be inoperable or stuck on or no bright, too. Sometimes this will similarly affect the exhaust fan operation or inside light, too.

Feel free to contact me directly (and please remind me of your full model number from the tag on the unit) for more information & help.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

William E. Miller, AS-EET
[email protected]
http://www.microwavedisplay.com