Question PC power keeps pulsing on and off?

Sep 19, 2020
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I'm not sure what's happened, it just decided to randomly stop, I finished building this just a few weeks ago, I have had the parts for a few years but basically always in the boxes still. When I do plug in or switch PSU switch on, there is just constant pulses. On off on off on off ... nothing else. I have my speakers plugged in and they make the on off sounds and the power led butting flashes with the noise.

I have tested the PSU with a paperclip and it works fine, and then I tried everything else including taking out the graphics card and rams etc. One time i even used the paperclip when everything was plugged in and the hard drives worked fine but obviously no power was going into the motherboard.

What's real odd is sometimes when I plug out the power cord and have the PSU switch off, it still makes that power pulse? ...

I'm unsure what's going on. Pretty sure I may have fried the mobo, but I just want to double check exactly what's wrong with it or could potentially be wrong before I have to fork out more money for what is basically a brand new PC🤦‍♂️
 
Sep 19, 2020
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Not just psu, all parts like motherboard/cpu/ram
Remember I have plugged out Ram and checked if that was the issue but again no power seems to be going into mobo.

MOBO - ASROCK 970 extreme4
Ram - 2x Hyperx Blu KHX1600C9D3B1K2/4GX, 2x Samsung 4gb 2Rx8 PC3-1600U-09-11-B1
CPU - AMDFD6300WMW6KHK

is that right?
 

Vic 40

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Well for one, that you can make the fan spin on the psu doesn't mean that it can power a system. Migth be that since used little or not the parts inside, likely capacitors, give problems when putting load onto it.
Since an older psu, think btw not that bad in it's time, might it be just this.

Can you test with another psu? maybe from a friend or loacla shop ...

Other thing might be that the motherboard needs a new battery, which is an easy cheap thing to replace. Maybe after a new battery that you can reset the bios to optimal default values and it will work fine. Put some time between replacing the batteries, like 10 minutes, and you would have done a clear cmos at the same time.

Other thing is that you can check via this list,
maybe something not connected right when installing parts like stand offs.

Did it btw work for a short while, cannot really get that clear from your first post.
 
Sep 19, 2020
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Well for one, that you can make the fan spin on the psu doesn't mean that it can power a system. Migth be that since used little or not the parts inside, likely capacitors, give problems when putting load onto it.
Since an older psu, think btw not that bad in it's time, might it be just this.

Can you test with another psu? maybe from a friend or loacla shop ...

Other thing might be that the motherboard needs a new battery, which is an easy cheap thing to replace. Maybe after a new battery that you can reset the bios to optimal default values and it will work fine. Put some time between replacing the batteries, like 10 minutes, and you would have done a clear cmos at the same time.

Other thing is that you can check via this list,
maybe something not connected right when installing parts like stand offs.

Did it btw work for a short while, cannot really get that clear from your first post.
Sorry, I am a little confused with your first point, " Well for one, that you can make the fan spin on the psu doesn't mean that it can power a system. Migth be that since used little or not the parts inside, likely capacitors, give problems when putting load onto it.
Since an older psu, think btw not that bad in it's time, might it be just this."?

These parts I have not really used except when i tested them and they've basically been in their boxes for years now, so they're basically brand new, that is if the parts I was given as presents were brand new when bought.

I will look into trying to borrow another PSU and look into buying a battery too.

Yes it was working for a few weeks before it started the power pulsing.

Also remember I said I had a feeling for some reason (don't know why), but I tested the PSU without it being plugged into the MOBO but other parts, and everything seemed to work then? such as the HDs powered up, the fans, etc.
 
Sep 19, 2020
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Also, Shouldn't the pulsing say something more? That it isn't that the power of the PC isn't starting up, but actually not getting enough Juice or something causing the pulsing?
 

Vic 40

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Even unused can de capacitors degrade, so might be a source of problems.

Do look at that check list i linked. Maybe test with one stick of ram which likely is suggested. Do that in the second slot from the cpu out (A2).

Tried a clear cmos?
 
Sep 19, 2020
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it could be a stuck power switch on your case

just try with the reset button on your case connected to the power on your motherboard this eliminate a broken power button on your case

this can also be the cause for random shut downs or turning a pc off and it not restarting
 
Sep 14, 2020
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Hmm, so I am assuming that you built it yourself? The power supply is decent in specs, that shouldn't be a problem. Kind of similar to the reply above, it may be an issue with your power button. Are you sure that you plugged in the front panel power button connectors in correctly? If not, that coukld be the issue. Otherwise, it may be your motherboard's BIOS that is giving you trouble. Try flashing it.
 
Sep 19, 2020
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it could be a stuck power switch on your case

just try with the reset button on your case connected to the power on your motherboard this eliminate a broken power button on your case

this can also be the cause for random shut downs or turning a pc off and it not restarting
Yes I thought of that, The thing is that it was working fine, I then plugged out the wires going to the mobo from the button. Still the same thing as soon as the power chord is plugged in or the PSU switch is turned on?
 
Sep 19, 2020
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Hmm, so I am assuming that you built it yourself? The power supply is decent in specs, that shouldn't be a problem. Kind of similar to the reply above, it may be an issue with your power button. Are you sure that you plugged in the front panel power button connectors in correctly? If not, that coukld be the issue. Otherwise, it may be your motherboard's BIOS that is giving you trouble. Try flashing it.
Doesn't the power have to be working to do that? the pulsing is an immediate thing, continuous off on off on, milliseconds in between.
 
Sep 19, 2020
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So jumper nr19 on the right lower corner of your motherboard,




Yeah I tried that, it didn't work, still the same pulsing. it's the pulsing that confuses me as it's like when the power is plugged in but switch is off or even sometimes a little after I plug the power out. I'll keep trying down that list I was sent in the meantime, but anything else will be useful. thanks
 
Sep 19, 2020
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Hi Guys, just an update, I've just inspected the CPU for a second time and I've noticed some bent pins. I'm unsure if I had missed it the first time I looked, but they're there now.

However, I'm still not convinced this is the cause of the power pulsing that is happening with the PC. As it isn't that it isn't starting/booting up, but pulsing of the power which is confusing.

It was working for a few weeks, before it decided to start pulsing, which means the CPU was perfectly fine right?

I'm gonna get another CPU and will let you know if nothing changes.
 
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Sep 19, 2020
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Bent pins need to be straightened. You only know afterwards if this was the problem or not.
SO I've straightened the pins and put it back in, still the same pulsing noise. I've also tried turning it on without the CPU in and still has the same pulsing issue, you would think it would change regardless of what happens right?

Is it worth getting another CPU?
 

Vic 40

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You're stil testing with 4 sticks of ram or just one? test with only one untill problems might be solved. Would start with a Samsung.

Problem might be motherboard as well. See no need for a different cpu right now.
 

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