Question PC kept cutting power but a new power cord seems to have fixed the issue ?

[zenonithus]

Hi all,

My PC kept randomly cutting power each day. I was about to change the PSU thinking it was faulty but when I changed the power cable and now it seems fine and stable. This has happened before and changing the power cable seemed to fix it then, so when it started happening again a year later I assumed the power cable wasn't the fix, but again it has proved it is.

My question is what causes the power cable to fail twice? Is it the wrong amp in the plug? Or something may have happened to faulter the cable? My pc fell over on its side once so that has made me think did it yanked the cable out a little to damage it as it was still powering to the pc? Just confused as to why the cable would die suddenly.

 

[bill001g]

My power cables never seem to fail. I will toss old equipment in the trash but keep the power cords....you know just in case. I now have a huge bin of them.

Unless you were to use one that is too thin for your power supply I can't see how it wouldn't work.

I guess if it was like a extension cord and you constantly plugged and unplugged them you could wear the metal out on one of the ends. I have a number of outdoor extension cords I have had to replace the end on because they no longer held the plug tightly.
I can also be the wall outlet these too wear out but again it is not common.

You could have also damaged the connectors on your power supply. If you for example bend one of the metal connectors and straighten it out it may now move a small amount due to heat and sometime not make good contact from time to time.
It is actually very hard to damage these you would tend to remember doing it. A damaged connector in the power supply although it can be repaired it can be a bit dangerous for someone who has not done it before.

 

[zenonithus]

Yeah the connectors is a good point, when the pc fell over on its side the cord could have caused damage, though it doesn't explain why a new cord seems to work fine. I've had the pc on most of the day and no power cut off. Before it was cutting off more and more each day until it was like 10 minutes in once I got into Windows. Yeah these leads are usually bullet proof and I'm sure it would work fine for a monitor. Maybe the PSU is more sensitive
One thing I noticed is that the powercord that seemed to cause the cut-offs has a 10 amp fuse. Are pcs supposed to have a specific amp fuse for the plug?

 

[bill001g]

Not sure what kind of power cord you are using if it has a fuse in it. All the ones I use are just simple plastic and wire.

 

[zenonithus]

so its basically the kettle lead that plugs into the PSU to the wall. The one I was using was 10 amp fuse, then the one that stopped cutting out was a 5 amp fuse. Though 10 minutes ago I plugged in my external ssd and the pc went dead. It wouldn't turn on no matter what. Then I swapped the power lead for the old one and works fine!? So it's as if the psu killed the new 5 am power lead as it doesnt work with the psu anymore, but it DOES work with my monitor?! I put another 5amp fuse kettle lead and it works again.

It looks as it the PSU is somehow damaging the power lead?? though the damage only seems to be when used with the PSU only. So not sure what is going on.

 

[bill001g]

If you are blowing fuses then the power supply is likely defective.

Even 5 amps at 240 volts is over 1000 watts that is a huge power draw. So a computer power supply should not blow a 5amp fuse....I guess if you have a 1600watt one it could.

 

[zenonithus]

Yeah it happened again with the new 5amp lead. It seems when the computer is in sleep mode it doesn't wake up and even after turning it off at the mains and on the PC fails to turn on ( there is a flash of light as it it is about to but then dies) then the 5amp lead will no longer work with the PC. I've yet to see if it happens with the 10amp. At this rate I will run out of power leads

So my main question is my PSU is 650 watts, what would be the correct fuse amp to have in the plug of the kettle lead?

Also could using the incorrect power lead plug in terms of fuse amp, damage the PSU and cause this instability?

 

[bill001g]

Can you replace the fuse in the power lead.

The math is pretty simple. Take the watts and divide it by the voltage which I assume is 240 in your case. 650/240 gives 2.7 amps. So if you blow a 5amp fuse there is something very wrong with the power supply.
Using a cord with the wrong fuse size will not damage the power supply. I had never seen these before you talked about them and it seem they are used in the UK. In the USA there are no fuses in the power cords and the voltage is only 120 so the amps being run through the wire is double.

Fuses are a safety thing. They are designed to blow the fuse out before the cable melts for example. They are only sort of used to protect the end equipment. If the power supply would short out and there was no fuse of any kind anywhere it would actually melt the power supply and likely start of fire.
It does not stop or cause the equipment to fail it just prevent the failure from killing you.

I strongly suspect there is something very wrong with that power supply. I would replace it before it damages the expensive parts inside your computer.

 

[zenonithus]

Thanks man, that clears things up more on the amps I need to be using. I read the specs and it says 5-10 amps is fine. Now I have a different issue in that the PC wont power on at all. So power is going to the motherboard as the lights are on, though pressing the power button there is the flash of lights then it shuts off. So is it possible the PSU is faulty now? no cable seems to work anymore.

 

[zenonithus]

Just an update on this, the fault seems to be my PSU. I dont think it had enough power, so swapped it for a higher power version and seems to be fine now.