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The Daring Dufas[_7_] The Daring Dufas[_7_] is offline
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Default Microwave fuse question

On 1/7/2011 9:43 AM, Tony Miklos wrote:
On 1/6/2011 11:20 PM, The Daring Dufas wrote:
On 1/6/2011 9:54 PM, Tony Miklos wrote:
On 1/6/2011 10:27 PM, The Daring Dufas wrote:
On 1/6/2011 9:04 PM, Tony Miklos wrote:
On 1/6/2011 9:39 PM, The Daring Dufas wrote:
On 1/6/2011 7:05 PM, Tony Miklos wrote:
On 1/6/2011 8:25 AM, wrote:
On Jan 6, 1:28 am, The Daring
wrote:
On 1/5/2011 11:55 PM, Steve B wrote:





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

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- Hide quoted text -

- Show quoted text -

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..

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.

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

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.

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/aeroelectri...es/faston3.pdf

TDD

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.


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 250°C which is quite hot. PS, you
also need a good crimp tool. :-)

TDD


The ambient temp around the fuse probably never exceeded 100ºF. 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.


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