Microwave fuse question

I just got a BIG combo oven and microwave from my daughter. She said she had not used the microwave for a year and a half, and my son in law isn't mechanically inclined, so they got a new one. Oven, MW combo and all.
I pulled the panels and looked for the obvious. The fuse was quite corroded. I pulled it, polished the ends. It's a small Buss type fuse. Cleaned the contacts, too. Reassembled.
Had to trim the door hooks a slight tad, too to get it to release when you push the release bar, but works like a charm now.
I have to put a plug on it tomorrow, and test, don't know if that solved the problem. Could the corroded fuse on the end have caused it to stop conducting electricity? I did a continuity check on it using a 9v. battery and tester, and the reading was right at 9v., so I think the fuse is good.
Just wondering. Don't know what got in there to cause the terminals and fuse ends to corrode. Hope it works tomorrow when I fire it up.
Steve
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On 1/5/2011 11:55 PM, Steve B wrote:

Corrosion kills a lot of electrical stuff and a bad connection can cause a terminal to heat up and burn up. This can also happen to a fuse with a bad connection. It will get hot and pop. Here's a link for some easy to follow repair advice:
http://www.gallawa.com/microtech/index.html
As far as what caused the corrosion, it could have been caused by an oven cleaner spray. I had to repair a commercial refrigeration unit that a moron had used spray oven cleaner on to remove some built up grime but some of the chemical got into the electrical control box wreaking havoc with the wiring and power switch.
TDD
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wrote:

corrosion might have been caused by arcing at fuse. the contact detoriates and heats blowing the fuse.
i would consider replacing the fuse holder if fuse blows again.
the machines i repair for a living do this a lot..
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On 1/6/2011 8:25 AM, snipped-for-privacy@aol.com wrote:

I had similar problems with the 1/4" glass fuses, mostly with 30amp fuses. It happened almost from the time they were new. I'm sure someone will tell me I'm reckless and dangerous but it always worked for me. First a new fuse and fuse holder. Run it for 10 minutes. Unplug then feel the fuse and holder. If it's hot or even a bit warm I installed a second fuse holder parallel to it and installed 2 15 amp fuses in place of the one 30 amp. The fuses and holders then stayed cool, and when the bridge diode it powers goes bad, they blow and save the transformer. I never had a call back on one of those mods.
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On 1/6/2011 7:05 PM, Tony Miklos wrote:

Were you using the 1/4 inch Faston connectors to hook up the wiring? In appliances, I'll always use the high temp nickel plated Fastons for making connections. Not all slip on connectors are created equal.
TDD
TDD
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On 1/6/2011 9:39 PM, The Daring Dufas wrote:

The originals from the factory were standard Buss fuse holders rated at 30 amps, as were the ones I used to replace them with. At the time I looked for higher rated fuse holders but couldn't find any. I had measured the actual current but I don't recall what it was. It probably would have worked from new if it wasn't turned on 12 to 24 hours a day. I looked up Faston but I'm not sure of what you were referring to.
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better to use solder fuse holders, i like the idea of parelling them to prevent heating.
as i said earlier i fix machines roll laminators that use these glass fuses, and fuse blown is pretty common:(
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On 1/6/2011 10:18 PM, snipped-for-privacy@aol.com wrote:

Yes, whenever heat is/was a problem, as often as possible, I solder direct to the fuse holder. Unless.... do you mean using fuses with pig tails? I suppose that may have worked!

Could be job security? ;-)
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On 1/6/2011 9:04 PM, Tony Miklos wrote:

The 1/4" tabs that you slide a flat female connector over. This will explain it:
http://preview.tinyurl.com/256d49o
You can see the specs on all different types at the above link.
http://www.matronics.com/aeroelectric/articles/faston3.pdf
TDD
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On 1/6/2011 10:27 PM, The Daring Dufas wrote:

OK, I think I know what you are getting at... a cheap connector getting the fuse terminal hot? If so, that was the first thing to go, I soldered the wires to the first new fuseholders. The original wire terminals connected to the fuse holders were also a problem. I even (sometimes) put a 1.25" cut off part of a 1/4" bolt in the fuseholder to keep the fuse terminals from overheating from soldering. Nothing worked until I went with 2 fuses parallel.
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On 1/6/2011 9:54 PM, Tony Miklos wrote:

It's a good workaround, yet, a single high temp fuse holder with nickle plated connectors and a ceramic barrel fuse will hold up. If you ever repair electrically heated appliances, the nickel plated connectors of all types are a necessity. I also use high temp wire along with the nickel plated connectors for electric stoves, hot plates, etc. The appliance repair parts suppliers carry the wire but I often go by the electric motor rewind shop where the guys will give me a few feet if I only need a small piece. Oh yea, if you look at the specs, I believe the nickel plated connectors are rated at 250C which is quite hot. PS, you also need a good crimp tool. :-)
TDD
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wrote:

Tens of millions of these work just fine with one fuse as engineered. His fuse was not blown by his account. He had corrosion on it that was probably the result of a gap in the door.
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well on microwaves always use ceramic fuses, that helps keep them cool
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On 1/7/2011 7:07 AM, jamesgangnc wrote:

Hummmm, I wonder if the acid from the tomatoes in my spaghetti sauce has the ability to corrode the electrical contacts in my microwave oven. If garlic could corrode anything, I'm out of luck. :-)
TDD
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On 1/7/2011 8:07 AM, jamesgangnc wrote:

You may be mixing up the thread. I'm the one running two parallel fuses, and the fuse holder problem was widespread affecting most everyone of these machines ever made. By the way, I'm talking about an old "Pole Position" video arcade game, not a microwave oven.
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Tony Miklos wrote:

I remember Pole Position, although to be honest I liked MonacoGT better. It was earlier, and more simple, but somehow it was more engrossing to play (except for that damn tunnel).
Jon
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On 1/6/2011 11:20 PM, The Daring Dufas wrote:

The ambient temp around the fuse probably never exceeded 100F. The heat problem was from the resistance between the fuse and the fuse holder. They were rated for 30 amps but simply didn't do the job. And I have a good crimp tool or two, but were I had the problems I directly soldered the wires to the fuseholder to eliminate a poor connection to add to the problem.
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On 1/7/2011 9:43 AM, Tony Miklos wrote:

I think you mentioned it was in an arcade game cabinet, I've replaced the little AGC or 3AG fuses and holders with the larger form factor fuses and holders like those I've used in industrial control cabinets. I wonder if covered fuse holders would work better? The game cabinets remind me of a lot of computer equipment where everything gets covered in dust. I've had dust deposits get into electronic equipment, take up moisture from the air and short stuff out and cause corrosion. I love opening up POS "Point Of Sale" computer and digging out the dust elephants and dust rhinoceroses. :-)
TDD
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There are multiple safety devices associated with the door latches. That you messed around with the latch hooks suggests that the door was not aligned properly. Regular service guys carry leak detectors with them to use if they have to work on the door or it's associated locking mechanisms. The service manuals all call for a leak test after service in that area of the unit.
I'm not saying that you should get a leak detector. But I am saying the you should have tried to make it work without modifying the door parts. And now that you have modifed the parts it might be harder to get it aligned correctly and the safety devices to work properly. So you might end up microwaving yourself. Had all the kids you plan on having?
Given that the door was not operating properly I'm inclined to suspect a safety device rather than the fuse. You are correct, it's just an ordinary buss type fuse. If the door is not closing properly then you may have steam from cooked food getting into parts of the unit where it normally wouldn't. That might explain your corrosion.
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besides a microwave leak..... hazardous at best.
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