15 years ago I had a microwave that failed like that. I took the cover
off, knowing there was almost nothing I could do to fix it. However,
what was wrong was one of the few things I could fix. A blown fuse. A
replacement was about 69 cents at Radio Shack.

I still use that microwave.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin

A fuse is likely. It's very typical for them to die of old age. You
need an exact replacement though in terms of type and amperage. This
fuse is part of the protection circuit that protects not only the
microwave oven, but you.

I just had one die (A Sharp 1000 watt model). For about 3 weeks, I
could smell something burning when I used the microwave. Then
suddenly no power...

The problem is that my fuse melted the fuseholder and the plastic
support underneath. It still could be fixed, but at $69.95 for a new
replacement oven... the price alone of not having to clean it did it
for me.

Fuses also blow when there is trouble with the interlock switches.


Anything that draws high current, such as air conditioners, microwave
ovens, etc. can be trouble for fuses.

Beachcomber