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pc not turning on when cpu 4 bin cable is plugged

M

makuke12

Joined
Feb 25, 2022
Messages
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System Specs
Motherboard GIgabyte GA-965P-DS3
Cooling Air cooled
Memory 2x2gb DDR2
Video Card(s) Geforce 960
Storage 500gb + 256gb +60gb hdd-s
Display(s) Samsung tv
Power Supply Xilence 500w
So i have this problem when 4 bin cpu cable is connected pc doesn't turn on but when it isn't it turns on. Can someone tell me what can cause this? I think its psu but im not sure.
 
Last edited by a moderator:
That is going to be a short in the motherboards mosfets. It;s triggering the power supplies short circuit protection to prevent damage.
 
JrRacinFan said:
That is going to be a short in the motherboards mosfets. It;s triggering the power supplies short circuit protection to prevent damage.
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Can i fix it?

Or do anything about it?

JrRacinFan said:
That is going to be a short in the motherboards mosfets. It;s triggering the power supplies short circuit protection to prevent damage.
Click to expand...
also my motherboard is GIgabyte GA-965P-DS3
 
makuke12 said:
Or do anything about it?
Click to expand...
New motherboard or a PC repair shop that has the ability to do voltage injection to locate/replace the MOSFETs causing the short. The only sure fire way to correct it. Is the PSU modular? If so when you disconnect the eps 4 pin, do you also disconnect it from the PSU?
 
JrRacinFan said:
New motherboard or a PC repair shop that has the ability to do voltage injection to locate/replace the MOSFETs causing the short. The only sure fire way to correct it. Is the PSU modular? If so when you disconnect the eps 4 pin, do you also disconnect it from the PSU?
Click to expand...
My psu is not modular and i also think that it will send power to wires that aren't connectes as well
 
makuke12 said:
My psu is not modular and i also think that it will send power to wires that aren't connectes as well
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Oh ok. Well aside from potentially replacing the motherboard, 1 other you can test is if everything works outside of the case on a cardboard box. My suggestion was going to be if it is modular that could potentially have a short in it.
 
Most probably cpu vrm went bad (thus by providing the 12v cpu power you are triggering the scp and the psu "clicks" for a split second before shutting down. Usually its easy&cheap (with technical experience ofc) to locate the shorted mosfet on the motherboard and replace it BUT unfortunately there is also a great chance that the cpu was killed by the short (in some cases the 12v goes into the cpu which instantly kills it), its not not 100% guaranteed but you gotta be prepared to replace the cpu since unlike mobo you cant fix them.
 
But would pc start then? My pc starts then runs for 10 seconds or so then does it again and then shuts off. Also fans work during that
 
makuke12 said:
when 4 bin cpu cable is connected pc doesn't turn on but when it isn't it turns on
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Which one is it? What you're now describing is totally different behavior altogether.
 
makuke12 said:
But would pc start then? My pc starts then runs for 10 seconds or so then does it again and then shuts off. Also fans work during that
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that sounds like it is trying to POST but fails. It cannot POST with the cable unplugged, because the CPU isn't getting the required power with it unplugged. that behavior would be expected when EPS cables are not plugged in. the POST will basically think there is no CPU installed. I assume same thing would happen if the CPU did in fact get fried from the potential hardware issue others alluded to

on the flip side, it does absolutely nothing if the cable is plugged in and you try to turn on the PC. others pointed out, that could mean a hardware problem and you would need to take it to a professional to at least fix, if not also diagnose and then fix. but actually before that, if possible, it would be a good check to eliminate the CPU being dead as a variable and swap in a known working CPU....if you have one or are willing to find a cheap compatible one on ebay or your countries equivalent of ebay. you could also put your CPU into another known working motherboard to help understand these variables.

what do you use this system for? is this is a purpose built retro system, or is it your daily driver system? I ask because this system is a bit long in the tooth by today's standards. if you want this system for a specific use case then I understand the desire to fix it. but if it is a daily use kinda PC, I suggest you weigh the costs of fixing this system, or investing in one that is a little newer. it may no long make financial sense to dump time/money into something so outdated
 
From what's described it sounds like he's plugging in the wrong one if it has the split 4-4 CPU power plug, most PSU's there days have it.
I've done it before and that's exactly what mine did in how it behaved.

Thing is with a split 4-4 CPU power plug you CAN plug in the wrong one if it's turned 90 degrees from where the socket tab for the plug's latch is, the wrong plug will just go right in as if it's the right one but it's not.
I found the problem and noted I had done that, switched plug ends, made sure it was going in the right way and the system then booted.

OP - Make sure you aren't plugging in the wrong side/half and also be sure when it's in, the little latch/hook is going where the tab for it to lock onto is.
 
makuke12 said:
So i have this problem when 4 bin cpu cable is connected pc doesn't turn on but when it isn't it turns on. Can someone tell me what can cause this? I think its psu but im not sure.
Click to expand...
Swap to a known working psu and report back

It is still called P4
 
imo it's the motherboard. Have the same problem on a p6t deluxe, pretty sure board is kaput. Tried known good psu too, same, guessing his will.
 
Bones said:
Make sure you aren't plugging in the wrong side/half and also be sure when it's in
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Thank you for mentioning this. I was taking a big assumption that OP knew how to hook up a power supply but yes youre right, people will be people and it's pure human to error making an oopsie lol
 
Tigger said:
imo it's the motherboard. Have the same problem on a p6t deluxe, pretty sure board is kaput. Tried known good psu too, same, guessing his will.
Click to expand...
I Have a Spare P6T deluxe board and ram free to a good home...
 
What's the story here? Did you upgrade the CPU? Did the PC stop working and you figured out removing the 4-pin made it work?
 
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