Got a microwave that won't heat food anymore. On top of that, it smokes and it smells like burnt plastic if I turn it on for more than 20 seconds. What's wrong?
Get a repair man in your local area and have him checked on the problem of your microwave. In that way, you will know what has gotten to your microwave.
Microwaves have very high voltage and can be dangerous to work on on your own. If their is a very strong smell and your oven is no longer heating it might point to the Magnetron. However, have this checked out by a professional just to be safe. Hope this helps.
If it's still under warranty, get it replaced. If not, I'd agree with SJN about throwing it away. Or an even easier option would be to put it on Craigslist in the "Free" section and say that it needs to be repaired. Some mechanically savvy person might want it. Good luck with it.