Microwave oven catches on fire. Repairable?

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.php?quickkey=ezsdlmtxmvt&thumb=4
And one of the exterior:
http://www.mediafire.com/imageview.php?quickkey=csddinoyvgd&thumb=4

Well, I think the only thing you can do is turn this into a game, and mebbe make some money: Take bets on just how long this oven will last--2 bangs, 5 bangs, 10 bangs....
Clearly you don't want to walk away from this thing while it's on. In fact, you might just want to unplug it when not in use. If it were me, I would do as I just said, and use it under a watchful eye, and start shopping for a replacement now.
It might could be that in some previous use, food "exploded" into some internal connection, and it occasionally burns off, energetically. The only solution is to take the whole thing apart, clean what's dirty, mebbe pull/re-seat the magnetron etc.
Either way, you got a crap shoot on yer hands. I would take it apart, as I think it might be inneresting, and imo you really don't have much to lose.

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Give the history of fire, I'd not want it in my house. For $60 to $100, there are all sorts of models with features probably very close to what you have. Repairing it will probably cost more than a new unit with a warranty.

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Clean the area up real well and get a new cover (wave guide). Some appliance dealers can cut you a new cover from bulk stock.
Might try this website...
www.RepairClinic.com

kjpro @ usenet.com wrote:
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And then sit back and wait for the next fire?
Surely you jest sir... <G>
Jeff

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appliance
No, clean the cabinet and replace the shield and it's as good as new.
That's the reason it happened the second time, cause he didn't replace the wave guard cover!

kjpro @ usenet.com wrote:
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I defer to your knowledge and experience, but my curious mind wants to know what material actually cought on fire. Was it part of that 2T of margarine which vaporized and combined with air to form a flammable mixture?
I can't recall reading any warnings about stuff like that, but like so many folks I don't always RTFM for "self evident" things like microwave ovens. <G>
Jeff

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the
mixture?
The cover is normally a cardboard material that has a special coating on it, very few are made of plastic.
The materail that caught on fire is a combination of food that has splatter on the wall of the oven over the last few weeks, months or years. This is a pretty common issue with microwaves.

DA had written this in response to http://www.thestuccocompany.com/maintenance/Microwave-oven-catches-on-fire-Repairable-230744-.htm : w_j snipped-for-privacy@yahoo.com wrote:
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A microwave may be repairable but the one that "occasionally catches on fire"?! Why even bother? Compared to having to deal with a major fire in the house started by this MW, shelling out a $100 or less on a replacement seems a total no-brainer to me.
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On Jul 3, 2:23 pm, info_at_air-space snipped-for-privacy@foo.com (DA) wrote:
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When the kid at Best Buy wants to sell me an extended warranty on a microwave, I tell him, "Microwaves are like toasters. When they quit working you throw them out." Frank

wrote:
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replacement
True, but for $5 dollars, this one can be fixed. :-)

(On fixing a microwave that has had fires develop in it more than once before)
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Would I want to be supervising it every second it was running in case the fix did not fix the right thing or in case there was more than one problem and not all problems got fixed?
One more thing: Cooking of popcorn requires some attention. Its rate of temperature rise accelerates after it is "done", especially in a microwave, and popcorn is normally as done as it should get before every poppable kernel has popped. Several months ago the Daily Pennsylvanian mentioned cooking of popcorn as being a major cause of fires in student residences. Extra vigilence is recommended if you try a different quantity or brand of popcorn, or a different microwave from one you are used to for microwaving popcorn.
- Don Klipstein ( snipped-for-privacy@misty.com)

On Wed, 4 Jul 2007 23:06:59 +0000 (UTC), snipped-for-privacy@manx.misty.com (Don Klipstein) wrote:
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Of course they're stupid, and known to have a water fight, take a ahower, study for a test, and go to sleep between the time they start the microwave and the time they turn it off.
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kjpro @ usenet.com wrote:
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If your not up to the repair, by all means knock yourself out and purchase a new unit.
However, I have repaired many microwaves that has this little issue and it's an easy fix. But I guess you just replace EVERYTHING when something little malfunctions!

usenet.com wrote:
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The issue of more than one fire is nothing, when he has NEVER actually fixed the real problem.
Ex. House fire, electrical wiring. Replace wiring in question or build a complete new home??????

w_j snipped-for-privacy@yahoo.com wrote in
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Samsung=consumables=disposables
...
Willing to bet your life on it?

Toss the stupid thing and buy a new one.

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This is why we are running out of space for landfills.
They're filling up to quickly, cause when things break, throw it away! :-(

Yeah...small problem.
On Tue, 03 Jul 2007 10:42:20 -0700, w_j snipped-for-privacy@yahoo.com wrote:
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