On Jul 3, 1:40 pm, wrote:
I have a small problem with my Samsung microwave where it occasionally
catches on fire. It last occurred when I was heating 2T of margarine
in a cup. I heard a bang, then saw the fire coming from behind a cover
which is presumably where the magnetron tube is. But I have used the
oven since, and it is still working fine. This same sudden fire
problem occurred many months before, where again, the oven worked fine
afterward. I have melted margarine like this many times since and used
the oven many times during those months, so I don't know why all of a
sudden it decides to go pyro on me.

That's the basis of my query: Can anyone tell me what might be causing
this, what to check and how to fix it so it doesn't happen again? I do
not want to risk fire when I am not around to monitor what's going on
with the oven, but at the same time, I do not want to replace it. I
have looked at getting another oven, but there's nothing that I like
as much as my Samsung. It has the size, the looks and the advanced
controls (ie. one touch, defrosting, etc) that I like.

This is a pic of what the damage looks like on the interior:

http://www.mediafire.com/imageview.p...mtxmvt&thumb=4

And one of the exterior:

http://www.mediafire.com/imageview.p...noyvgd&thumb=4

OK. I have repaired my Kitchenaid Microwave twice for this problem
and I am pretty sure I know what is going on and what needs to be
done. The microwave energy enters the oven from the magnetron through
a wave guide which is usually at the top of the oven. The wave guide
opening has a cover which looks like a plastic plate and in fact it is
made of a material similar to mica. After using the oven this plate
often gets splattered with food or grease and after a while it becomes
a kind of conductive surface which is not something you want in a
microwave oven. The food or grease eventually becomes carbonized and
allows trhe micorwave energy to arc over from the enrty point the
surface of the plate over to the metal on the side of the opening. On
my microwave it arcs over to a single sheet metal screw that holds the
plate in place. Once the plate gets blackened by the arcing, it
should be replaced. On my oven the part is relatively cheap; around $
10 or less. So the whole repair takes about two minutes. You remove
the screw, slide out the plate, clean up the edges of the waveguide
opening in case there is any carbon that has built up under the plate
or around the edges and then you put the new late in place and remove
the screw. It might be possible to clean up the plate (it's called a
wave guide cover ny the way), but I have just replaced the part with a
new one. That's the whole deal.

richf