Can a power lead fry PSUs?

NeilF · 30 Aug 2007 at 22:52

My sister's PSU went in her PC. I plugged in a spare old PSU of mine into her machine and it worked for about one second then died.

Yesterday, I plugged in a PSU out of another machine of mine and that worked fine. Booted the machine and ran it all fine!

Tonight I put that PSU back into the my machine and boom! Spark! Dead!

All these connections were done with same (her) power lead! Is it possible it could be to blame!? ie: It's shorting out in certain positions? These three PSUs were all old, but come on!

decto · 30 Aug 2007 at 23:24

Unlikely to be the AC in power lead but you never do know.

I'd junk it just in case.

Old PSU's a pretty tough, most have some sort of over current protection.

I could be that her lead has a fracture so it only works in some positions, thus simulating a number of dead PSU's

AD

NeilF · 31 Aug 2007 at 08:29

decto said:
Unlikely to be the AC in power lead but you never do know.

I'd junk it just in case.

Old PSU's a pretty tough, most have some sort of over current protection.

I could be that her lead has a fracture so it only works in some positions, thus simulating a number of dead PSU's

AD

Well, the lead was connected to my sisters PC when its PSU died.

The lead was connected to her machine when my spare PSU died (instantly) in it.

It was conencted to her machine when my other PSU worked OK in it mind.

But it was connected to my machine when I put back my PSU into it and it died (with a pop) instantly.

Seems just too much of a coincidence that three PSUs all go in a matter of minutes (of use) of each other!?

semi-pro waster · 31 Aug 2007 at 09:15

It is possible but a little bit unlikely that the power lead is the problem, however given the relative costs of a power lead and the PSU it plugs into I'd probably throw away the power lead and try another.

NeilF · 31 Aug 2007 at 09:20

semi-pro waster said:
It is possible but a little bit unlikely that the power lead is the problem, however given the relative costs of a power lead and the PSU it plugs into I'd probably throw away the power lead and try another.

The lead is already in the bin... It just has to be that lead! I cannot believe that three PSUs on different machines, at different locations, can all go within minutes (of use) of each other! The PSU from my old machine has been happily running for years...

To be honest I'm more concerned that I'm now two PSUs down and that it'll probably mean my old machine will end up on the tip

I'd just yesterday sold it to someone for £20... So chances are now the PSU is dead it will just end up at the tip - What a waste!

misterPK · 31 Aug 2007 at 09:24

Were you using surge protectors on them too? It could well have been spikes in the power supply rather then the lead.

PK!

Corasik · 31 Aug 2007 at 09:39

Doesnt really make a lot of sence, there's no way a lead can 'amplify' the voltage of the mains, a short would more likely blow the fuse on the cable, or trip the house fuses/circuit breakers.

AC is AC... If you reverse L and N, its still AC, and will still power anything, its just considered 'unsafe' as it reverses the position of the power switch on the device. (Power switches are virtually always on the Live wire.. or in a few rare cases both L and N), and a short to earth... likewise.

The only thing I can think of which could cause a lead to damage a piece of kit, is if the plug was so loose in the socket (at the PC end or the wall) that instead of giving a pure flow of power, it was 'arcing' across a narrow air gap, this could cause a lot of spiking and noise. If that was true though you would expect to see burn marks on the metal connectors on the PSU's power socket, or on the 3 pin plug on the lead, as arcing generates a large amount of localised heat.

rick827 · 31 Aug 2007 at 09:53

If you used an actual kettle lead ... ie 13 amp, it could blow it with a surge, but only with a surge..

Your PC lead should be 5A max rly, 3A would do

misterPK · 31 Aug 2007 at 10:14

Corasik said:
AC is AC... If you reverse L and N, its still AC, and will still power anything, its just considered 'unsafe' as it reverses the position of the power switch on the device. (Power switches are virtually always on the Live wire.. or in a few rare cases both L and N), and a short to earth... likewise.

Another bad thing about getting live and neutral wires mixed up is the position of the fuse. Normally the fuse is on the live wire, so when that blows the supply is cut off from the device making it safe. However, if there is a wiring fault and the fuse is put on the neutral wire, if it blows there's still a current getting through to the device, making it very dangerous.

So remember people, to be safe, go back to living in caves!

PK!

NeilF · 31 Aug 2007 at 12:55

rick827 said:
If you used an actual kettle lead ... ie 13 amp, it could blow it with a surge, but only with a surge..

Your PC lead should be 5A max rly, 3A would do

It's got a 5A fuse in it.... Just found out we have a device to test leads here at work. I'm gonna bring it in on Monday to test it. I just cannot believe that three PSUs can blow (on different machines at different houses) without something causing it! To much of a coincidence!!

NeilF · 3 Sep 2007 at 19:41

Well, the lead was tested and it annoyingly passed...

Personally I think it has to be that lead... Just too much bad luck, even for me!

WarBird · 3 Sep 2007 at 23:33

there's something wrong that's not just bad luck

NeilF · 4 Sep 2007 at 09:03

WarBird said:
there's something wrong that's not just bad luck

There is a large pentagram in the middle of my room that glows oddly from time to time!?

rick827 · 4 Sep 2007 at 09:10

NeilFawcett said:
There is a large pentagram in the middle of my room that glows oddly from time to time!?

That'd be radiation leaking from your plug sockets. I suggest plugging more PC's in to prevent the leak.

NeilF · 4 Sep 2007 at 09:37

rick827 said:
That'd be radiation leaking from your plug sockets. I suggest plugging more PC's in to prevent the leak.

Argh! Some odd multi-dimensional vortex has opened with demonic beings leaping from it.. The good news is no more of my PSUs have fried!

2StepSteve · 6 Sep 2007 at 16:42

Funny enough my mate had this happen to him a few days ago.

His PC killed two seperate PSUs, one that was working fine in another PC his dad uses.. its abit odd as to what is going on with it. When he tried the 2nd PSU saw a spark from inside and thats it.. lights out! PSU now fails to work with his dads PC.

Proper strange

NeilF · 6 Sep 2007 at 16:45

2StepSteve said:
Funny enough my mate had this happen to him a few days ago.

His PC killed two seperate PSUs.. its abit odd as to what is going on with it

Don't forget in my case that two supplies got fried in one machine and then another in a different PC. These were at two different locations, but all using the same lead :mad:

2StepSteve · 6 Sep 2007 at 16:55

NeilFawcett said:
Don't forget in my case that two supplies got fried in one machine and then another in a different PC. These were at two different locations, but all using the same lead

Ahh i see..as you say the power cable does look at fault, gonna tell my mate to take alook at his.

I really can't see how a problem like this would come about due to a faulty component on the mobo, or a short on the mobo.. theres safety cut outs on the secondary that would trip if too much current is drawn. Unless the PSU is shagged in the first place tho..