Anybody Ever Replace a Blown Fuse in a Power Supply?

LilHen

Golden Member
Apr 1, 2003
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I was flashing my BIOS late last night when all of a sudden, the damn computer turned itself off. I thought I saw a message saying that the flashing was completed successfully but it was all too quick. Usually, it would say hit any key to restart. I tried to turned it back on, but to no avail. I even reset the CMOS, but no go. After a few choice expletives, I went to bed.

After some careful diagnostics this morning, I determine that the PS was the culprit. It makes a high pitched, whiny sound when power is applied, but it won't turn on. I tried jumping starting the PS by connecting the green pin to ground, but got the same thing. I tried another PS and luckily the computer still powers on. What a relief!

This just goes to show, even if you take all necessary precautions such as employing a UPS/surge protector, things can still go wrong if Lady Luck isn't on your side. In my case, I would say I got lucky that the PS held on till the flashing was completed--it gave its last full measure.

Anybody have any idea what's wrong with my PS? It's a Liteon PS-6161-2H 160W for a HP Pavilion. I wonder if it's worth the trouble to replace the fuse at all (if that is indeed the problem). I've been hesitant to open it up to look inside because not enough time has passed for the capacitors to discharge. I could just put in a new PS, but the Liteon was 3/4 the size of a regular ATX unit, so a regular PS would barely fit without sitting on the HSF.
 

akira34

Golden Member
Jun 26, 2004
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I'd say you're better off just replacing the PSU than trying to repair it. Who knows where the real issue is. It could be a blown part, other than a fuse, and you'll spend more time hunting down the issue than it's worth.

BTW, send me the dimensions of the PSU. I might have one from a mATX case that will work for you. It's 180W I believe, so it will do fine for what you have.
 

LilHen

Golden Member
Apr 1, 2003
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Well, I removed fuse (250VF 5A), but I have no idea of how to check to see if it's shorted. Any help?
 

akira34

Golden Member
Jun 26, 2004
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Fuses usually either work or show a physical break in them. If there's no break inside the fuse (should be visible) then that's not the problem. If you can't see into the fuse, then replace it with an identical one and see if it works. If not, remove the fuse (for use on something else) and just toss the PSU.
 

LilHen

Golden Member
Apr 1, 2003
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Nope, can't see inside the fuse. Paper covering instead of glass/plastic. Gonna stop by Radio Shack to see if they have the exact fuse. Bet they're going to RAPE my as$. Too bad there aren't more Mom and Pop tech shops these days.
 

HardWarrior

Diamond Member
Jan 26, 2004
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Originally posted by: LilHen
Nope, can't see inside the fuse. Paper covering instead of glass/plastic. Gonna stop by Radio Shack to see if they have the exact fuse. Bet they're going to RAPE my as$. Too bad there aren't more Mom and Pop tech shops these days.

Fuses are cheap, no worries there. I am surprised that your PSU doesn't have a circuit breaker instead. Mine is just over 3-years old and it has one.

 

LilHen

Golden Member
Apr 1, 2003
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I went to Radio Shack and they checked the fuse for me with a multimeter (note to self: get one and learn how to use it) and they said its fine. What's this circuit breaker you speak of? What does it look like? Is it anything like house circuit breakers? TIA.
 

Zepper

Elite Member
May 1, 2001
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Very few PSUs have circuit breakers. Fuses can best be tested using a digital multimeter. A good fuse should read zero ohms (after all, a fuse IS a short circuit), a blown fuse would read infinite ohms. If your PSU makes any noise when powered up, then it's not the fuse - if the fuse was blown there would be dead silence. Don't expect competent assistance at RS - go to a local electronics parts store that serves the repair trade. You should get knpwledgeable help and a higher quality, name brand fuse (Littelfuse or Bussman) - though you probably will have to buy a 5-pack.

.bh.

:moon:
 

HardWarrior

Diamond Member
Jan 26, 2004
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Originally posted by: LilHen
I went to Radio Shack and they checked the fuse for me with a multimeter (note to self: get one and learn how to use it) and they said its fine. What's this circuit breaker you speak of? What does it look like? Is it anything like house circuit breakers? TIA.

It's a device built into lots of electrical supply and distribution systems that replaced fuses in lots of devices a while ago. When I was a kid a surge would mean a quick prayer that we had a fuse, and if we did, a trip down to a scary residential basement. Circuit breakers made the prayer part go away and all we had to do was press a button to reset power flow. If you had one it would look like a raised plastic circle with a small recessed button in the middle, flush with the surface around it. Based on what you've said, I doubt you have one though.

 

BonzaiDuck

Lifer
Jun 30, 2004
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For a 150W PSU in an HP Pavilion, I'd say you're better off just getting a new power supply.