I just bought a used Whirlpool AT 317 microwave oven and although it works just fine when I turn it on the fan in the back is making an awful noise. I do notice there is some dust in there (like always in household equipment) but I can't imagine this is the main culprit. Does anyone have a solution for me?

SOURCE: Turntables doesn't work and makes horrible noise

Replace turntable motor. Not really that hard to replace or expensive. Remove all screws holding bottom panel (usually three across each side and one to three in front) to gain access to the turntable motor. The panel will hinge in the back.

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I have seen this specific problem. and I solved it.

It's the fan "bouncing" against the motor housing. Nothing wrong with fan -- design flaw. The way I solved this problem was to shim the fan mount so the fan was at a slight angle off level -- this keeps the shaft from moving in and out and the fan banging against the housing.

Here's a link discussing your queston about making an air compressor from a refrigerator compressor.

http://www.volksrods.com/id36.htm

SOURCE: Sharp Microwave Oven Model R-403kk-T

Are you talking about the light inside the microwave? The front vent I think will allow you to get to the bulb. Should be a couple of small scrrews holding the vent cover on, remove them take vent off. Start it up again and see if the light bulb wiring or socket is arcing

SOURCE: Frigidaire Oven making vibration noise when

This usually is caused by a bad convection fan motor. This is something that you should have a technician replace, but ask for a price quote first. Fairly expensive to fix and usually very complicated to get at. Good Luck, Appliance Specialists

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Morison,
The same thing happened to me about a week ago. I was preheating our electric oven, heard a very loud bang/pop. Checked and the oven had PF (power failure) I went downstairs and the breaker was tripped. Came back upstairs and to look at stove, the burners are working fine so I continued to preheat oven after a half an hour the oven was only slightly warm. Did you ever find out what was wrong?