Replace fuse with different type?

[Sniper82]

Had the power supply go out on a 19" LCD TV and pinpointed it to a bad fuse. I looked local and couldn't find one. I am curious if anyone on here knows enough about this stuff if it was safe to use a different type of fuse but same(15a) rating?

Thought about soldering a fuse holder on and using a normal 15a fuse.

 

[DaTT]

I see no problem with this as long as it is the same rating....but I am not a professional.

 

[lxskllr]

You want the same type also. Slow blow, or regular. Like DaTT, I'm no electrician, but putting the wrong style in could lead to frequent fuse changes, or excessive wear on the electronics.

 

[CallMeJoe]

You want the same type also. Slow blow, or regular. Like DaTT, I'm no electrician, but putting the wrong style in could lead to frequent fuse changes, or excessive wear on the electronics.

Fuses are not there to protect electronics; there's no fuse made that's fast enough for that. Fuses are there to prevent fires. Using a too-large fuse or a slow-blow fuse where a standard fuse is required degrades that fire protection.

Sniper: what details can you give on the original fuse? There should be more markings than just a current rating.
FWIW, I find 15A rather large for a TV unless it's as 12 VDC powered set. 15A at 115V yields ~1.7KW, which is space-heater range, not television.

 

[edro]

Lots of fuses are used to protect electronics. Their primary purpose is to protect from fire, but Fast Acting fuses are also fast enough to protect many devices.

If you use a fast acting fuse of the same voltage rating (or higher) and the same current rating, it should work fine.

I also agree that 15A seems large, unless it is on the DC output side.
Whatever caused the 15A to go might still be a problem and may blow your next fuse.

 

[Sniper82]

My bad I got bad eyes. Its a BE5 T3.15a Slow Blow. So its 3.15a not 15a.

 

[pcgeek11]

Yes it is OK to do what you want. Make sure you use the same specifications:

Voltage, current and slow blow.

As posted above I would be wondering why it blew in the first place...

I am a professional with 37 years experience.

 

[Sniper82]

Well put another fuse on it and it blows it instantly. With the PSU connected or disconnected. Guessing it in the PSU somewhere but its out of my hands now. Guess I'll try to find a replacement which will take some luck. The TV got knocked over when someone tripped over the power cord. It gets no power whatsoever.

 

[BUTCH1]

Well put another fuse on it and it blows it instantly. With the PSU connected or disconnected. Guessing it in the PSU somewhere but its out of my hands now. Guess I'll try to find a replacement which will take some luck. The TV got knocked over when someone tripped over the power cord. It gets no power whatsoever.

Check the diodes or regulator transistor in the PS circuit, chances are one of them is blown..

 

[LurkerPrime]

Fuses usually just don't blow for the hell of it, so replacing a fuse without adressing the underlying problem will usually just result in blowing another fuse.

Amazingly I thought they would be practically giving 19 inch tvs/monitors away these days, but apparently they are still $100-$150. Look at this as an opportunity to upgrade to something better.

 

[Analog]

use a penny. Will work every time.

 

[DaTT]

When I was into car audio, I had a 30a fuse off my main power line from my battery. It blew from time to time, but if I couldn't get a replacement until the next day, I used to wrap it in foil to complete the circuit. Worked like a charm.

 

[pcgeek11]

When I was into car audio, I had a 30a fuse off my main power line from my battery. It blew from time to time, but if I couldn't get a replacement until the next day, I used to wrap it in foil to complete the circuit. Worked like a charm.

Not too smart are ya? Does up in flames mean anything to you.

 

[JulesMaximus]

You want the same type also. Slow blow, or regular. Like DaTT, I'm no electrician, but putting the wrong style in could lead to frequent fuse changes, or excessive wear on the electronics.

Or a fire...

 

[Sniper82]

Fuses usually just don't blow for the hell of it, so replacing a fuse without adressing the underlying problem will usually just result in blowing another fuse.

Amazingly I thought they would be practically giving 19 inch tvs/monitors away these days, but apparently they are still $100-$150. Look at this as an opportunity to upgrade to something better.

well I got a 42" and a 26" LCD. This was just given to me. Thought if I could fix it would make a good little extra TV for whatever.

 

[Rubycon]

When I was into car audio, I had a 30a fuse off my main power line from my battery. It blew from time to time, but if I couldn't get a replacement until the next day, I used to wrap it in foil to complete the circuit. Worked like a charm.

If it was blowing due to playing it hard or too low of a speaker impedance, sure covering it with foil will keep it playing! However if the power supply in the amp shorts across the line and you don't have a fuse further up do expect trouble like a fire.

When a fuse is replaced and the replacement blows immediately your power supply needs to be repaired. Depending on the circuitry it could be a shorted diode or transistor.

Also it's VERY important to replace the fuse with not only the same capacity (amperage) but voltage as well. Why? Interrupt rating is determined by voltage and amperage. If you replace a 10A 250V "bussman" type glass fuse with a 10A automotive fuse and there is a fault that automotive fuse (most are rated 32V DC, for example) is likely to explode and can even allow an arc to continue long enough to do extensive damage or even start a fire. ALWAYS use the correct fuse.

 

[Sniper82]

what setting on my multimeter should it be on to test transistors and diodes? Also what rating would a bad/shorted one show? Or is other equipment needed?

 

[edro]

what setting on my multimeter should it be on to test transistors and diodes? Also what rating would a bad/shorted one show? Or is other equipment needed?

http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

 

[bruceb]

Everything mentioned above pretty much covers it.
Fuse blow due to a short (in which case the fuse will be black inside) or due to a small overload or surge. In this case, it will be a nice clean break in fuse wire.
After you find the problem, replace with same voltage and amperage ratings. Enclosure type, such as 3AG Glass or ceramic body can be critical in certain areas and you should use the same type. It does not matter if the fuse is Soldered in or installed into a fuse holder. Either way works fine.

 

[Sniper82]

looking at the replacement fuse again its only 3a. The extra .15 wouldn't make a difference whether it kept blowing or not? Or would it?

 

[futuristicmonkey]

Could you take some pictures of the area? If the input fuse is blowing and you're not seeing any smoke from other components on the board its bound to be a large component. If you're lucky, we might be able to figure out what happened/which component has failed.

 

[pcgeek11]

looking at the replacement fuse again its only 3a. The extra .15 wouldn't make a difference whether it kept blowing or not? Or would it?

It is a slow blow fuse, the extra 0.15 would not make any difference at all.

You have to remove the Diodes and Transistors out of the circuit to test them and will probably require un-soldering and soldering them back.