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What does a blown fuse look like?

post #1 of 11
Thread Starter 
As seen in my post below, my subwoofer stopped working today. In my instruction manual, it says check to see if the fuse is blown. I took it out and it says to check to see if the filament is in place. If it is out of place, the fuse is blown.

Well, I'm looking and I see a silver piece of something in the centre, but it's there. How can I tell if it is out of place? It does look rather slanted, almost leaning against the glass... does that mean it's blown?

Thanks.
post #2 of 11
Got a DMM? Check continuity. (Never had to deal with this myself, but I assume that's how to test them.)
post #3 of 11
The DMM trick should work... Generally it is pretty obvious when they are blown because they blow rather... uhhh... violently in my experience. Is the glass cloudy at all?
post #4 of 11
My exerience in electronics has shown that blown fuses are often hard to impossible to spot. We've troubleshot components where the fuse looked good to the eye, but didn't work. A slight overcurrent can blow a fuse, while an internal short can blow it and make it more visible.

One of two ways to see if it works. One is use a multimeter. The next is to rig up a flashlight with the batteries and some wire to pass the current thru the fuse on its way to the bulb. If the bulb lights, good fuse. If it doesn't, the fuse is blown.
post #5 of 11
If the fuse is blown, the filament will be disconnected at one of it's ends. Sometimes this is noticable, sometimes it isn't. Look carefully and see if the ends are visible. Try tapping the fuse and quickly look to see if the filament is bobbing around like a lose wire. If you don't have a meter or access to the wires of a flashlight or small battery powered motor, take it to Radio Shack. They'll test it for you and you can purchase a replacement there if you need to.
post #6 of 11
Or for a wiseass answer.... Exactly the same as a new one.


You can really only check check with a Multimeter. I once made a continuity tester with a PP3 battery, a bulb holder, couple of bits of wire and two crocodiel clips....
post #7 of 11
this is what it sounds like.




Sorry couldn't resist. If it is the glass tube type the thin wire will be broken towards the center. If it is a blade type agian you will see a break. The best way is to check with a multimeter for continuity. Some amps fuse look like resistor and just look burnt when blown.
post #8 of 11
Fuses are pretty cheap.
If you don't have a multimeter then just take the old one to the store and get a new one just in case.
post #9 of 11
"What does a blown fuse look like?"

Satisfied and content
post #10 of 11
Thread Starter 
Thanks for the witty, but useless retorts, ladies. For the rest, thank you as well.

Fortunately, it turned out that it was merely a blown fuse that was replaced today for a couple dollars, and everything is now peachy. Funny how that works.
post #11 of 11
you're welcome.
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