(Bob Ladbury) writes:

My wife just toasted a couple of rice crackers and cheese (on a
regular plate) in our Samsung microwave oven. The thing seemed to have
caught on fire inside the oven, but as there was no metal on any of
the food or plate, I don't think that caused it. There was a wild
flash, buzzing noises, then before I had the chance to run to the
circuit breaker, things died down... Well, the light in the oven is
still working, but the right side of the oven is charred so badly
(just above a small panel on the side wall), that it caused a rupture
in the panel. I am of course assuming the oven doesn't work any
longer, and is probably not repairable, due to the small hole in the
side panel. Does this sound familiar to anyone? The oven worked
perfectly earlier today, and since Ive never seen this happen before,
I'm wondering what went wrong with this device?

If by "side panel" you mean the mica/plastic waveguide cover, damage
to that isn't a serious problem. In fact, you can remove that panel
and it will work fine - it just prevents debris from getting into the
waveguide.

You had a very small load in the oven (the cheese on a couple of
crackers). Feeding 1000 W into that load it's not surprising
there were fireworks.

Without seeing it, now ay to know if there is more than cosmetic
damage but it probably won't hurt to clean up the charring as best
as possible and do a water heating test to see if the oven is still
working.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

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Required to have a service technician, authorized to work on the Samsung
Item, evaluate the unit. Then determine if the cavity damage is cosmetic or
permanent. They will also be able to give you a cost estimate of the item's
repair cost. BTW is it a tabletop unit or under-counter?? At least having
the model number would clear that up. As Sam posted, try cleaning the
charred residue from the cavity wall and put some water into the unit to see
if it functions. A measuring cup full of water should suffice.
"Sam Goldwasser" wrote in message
...
(Bob Ladbury) writes:

My wife just toasted a couple of rice crackers and cheese (on a
regular plate) in our Samsung microwave oven. The thing seemed to have
caught on fire inside the oven, but as there was no metal on any of
the food or plate, I don't think that caused it. There was a wild
flash, buzzing noises, then before I had the chance to run to the
circuit breaker, things died down... Well, the light in the oven is
still working, but the right side of the oven is charred so badly
(just above a small panel on the side wall), that it caused a rupture
in the panel. I am of course assuming the oven doesn't work any
longer, and is probably not repairable, due to the small hole in the
side panel. Does this sound familiar to anyone? The oven worked
perfectly earlier today, and since Ive never seen this happen before,
I'm wondering what went wrong with this device?

If by "side panel" you mean the mica/plastic waveguide cover, damage
to that isn't a serious problem. In fact, you can remove that panel
and it will work fine - it just prevents debris from getting into the
waveguide.

You had a very small load in the oven (the cheese on a couple of
crackers). Feeding 1000 W into that load it's not surprising
there were fireworks.

Without seeing it, now ay to know if there is more than cosmetic
damage but it probably won't hurt to clean up the charring as best
as possible and do a water heating test to see if the oven is still
working.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header is
ignored.
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(Bob Ladbury) writes:

Thanks Sam for the quick response. I believe the charring was indeed
over the mica/waveguide cover (there's a large high voltage
transformer right behind this part of the sidewall). The cavity damage
is cosmetic. I was mistaken that it created a hole in the cover, it
just melted a bit, but didn't go through. It's a 1000w tabletop unit,
and I have melted cheese and crackers dozens of times before over the
years in it, nothing like this happened, so I'm still not sure why it
did this time.

But let's say the unit works and heats up water, is it still necessary
to have it serviced? I don't want any risk of stray microwave energy
hitting me when I'm near the device, due to a damaged oven. But with
the cost of a service technician, I'd just as soon buy a new oven as
to have it serviced.

If only the mica thing cavity paint job is damaged, then no danger.
Sand down the cavity smooth and repaint with some non-toxic enamel
or microwave cavity paint if you're a purist. The cavity cover
can be replaced for about $6 for a sheet you cut to size.

First, test to make sure it actually still works.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.

I have melted cheese and crackers dozens of times before over the
years in it, nothing like this happened, so I'm still not sure why it
did this time.

Bob,
Most likely the cover over the waveguide was gunked up with debris from
food spattering (doesn't take much). It eventually carbonizes and starts
burning as it absorbs an increasing amount of microwave energy. That area
arcs back into the tube, hence the "fireworks".

But let's say the unit works and heats up water, is it still necessary
to have it serviced? I don't want any risk of stray microwave energy
hitting me when I'm near the device, due to a damaged oven.

If the cover is not badly damaged (you said it was not burned through),
just scrape off the burned area and clean and dry it well. See if any of the
metal around the waveguide opening is burned or there are any sharp edges. If
so, buff them down so they're smooth and paint them to prevent rusting.
Reinstall the cover and try the oven with a cup of water. It takes quite a
bit to burn out a magnetron. As long as the door closes properly (no missing
or broken parts), there is no real danger of microwave leakage.

Ray
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