Question about Whirlpool MH1140XM Microwave Oven
I have a fourteen year old microwave and oven combination. After warming some food, the microwave stopped, the clock display went blank and stays blank, the light does not come on, and the keypad is unresponsive. The regular oven works fine. I have replaced the 20 amp fuse with no improvement. Any suggestions?
I have a 13yr old above-range oven which quit when my wife cooked food in an aluminized foil wrapper (a small fire ensued!). This oven has 3 thermal protection units, on the magnetron, the chassis and on top of the food cavity. This last one had failed open, and since it's in series with the magnetron thermal protection unit and the main relay, nothing would work. MAT electronics sell the units for less than $4, but my problem now is to pick one with the appropriate temperature cut-off. They range from 200 to 300F.
Posted on Nov 18, 2006
Just so I understand, you replaced the fuse inside the oven? If so, I would suspect a bad thermostat attached to the magnetron. This device interrupts power when the unit gets too hot. I've included a representative photo. After so many years your magnetron may be bad, too. Once you get the oven working, if it cooks and doesn't trip the thermostat again, it may be okay. PLUS - It looks like this model has manual rotary controls. If so, it's common for those to develop bad contacts after so many years. I would consider that my third suspect. Those controls are called the thermostat (not to be confused with other part by that name that I discussed above) and the selector switch. One could easily be bad. You can check part prices at Sears online at http://www3.sears.com (the "3" is supposed to be there) Some other things that can cause a "dead" condition: - bad connections on the small circuit board where the fuse is mounted (if such a board is present) - bad connections in the wiring Good luck.
Posted on Nov 05, 2006
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.
This can often also affect the exhaust fan operation, too. The lights and fan can be inoperable or stuck on too.
Details of our service and critical safety information and disassembly information is at our site, linked here on Fixya:
Posted on Nov 28, 2007
In some Whirlpool models, there are more than one fuse, and two or more thermal devices which can interrupt power to the oven.
There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.
At our Web site, we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.
If you don't find yours, or if you want to look at it without disassembling the oven, you can download it here.
You can find helpful exploded view diagrams and order parts by entering your full model number from the tag on the oven here.
Please write back with more details if you need further help.
We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.
Posted on Mar 02, 2009
My Whirlpool/Roper microwave/hood combo has the same problem. I replaced the bulb twice, checked the bulb and it works, but not in the microwave. I wrote to Whirlpool asking about the problem. Haven't heard from them yet.
Posted on May 09, 2010
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