I was wondering if anyone might be able to help. Last night my microwave was working fine. This morning I tried to heat some water and a very loud buzzing sound came from the motor area. There was a small smell of plastic. Every time I try it the same thing. I have not let it run to see if it is heating since that seems to be a bad idea.

Any idea of what might have happened or what to check?

Thanks,
N.

Microwaves are expensive to repair. Also can be dangerous for diy project. Would be best to just replace from cost wise

Good advice. Just out of curiosity - does this sort of thing happen usually? I mean a sudden change in the behavior?

N.

The microwaves I see normally work or they don't. They are so inexpensive to purchase anymore I just don't get many calls on them. I would say yours is in the norm

The bearing that runs the fan on top could have frozen. My convection/microwave was designed badly that the shaft was supported in only one place. Needless to say, having access to a machine shop, it's supported in two places now and the bearings are protected better. The oven is huge and it cost nearly $800 scratch and dent when new in the 70's.