Pc wont turn on when cpu 12v atx is plugged in

Thomaspark

Thread Starter
Joined
May 9, 2021
Messages
6
When the 12v atx cpu plug is plugged in my pc wont start up. It will give a eighth turn on the fans then u can feel the psu pulse and nothing. When I unplug the 12v atx cpu cable the pc will start up. I already got a new psu.
Any suggestions?
 

Tanis

Shane
Joined
May 29, 2006
Messages
4,240
Can you provide more detail on the hardware you are working with?

What is the make and model of the following:

CPU?
Motherboard?
RAM?
Power Supply? Make, model and wattage
GPU? If a dedicated GPU is being used.

Is this a new build or a problem that has started with a previously working machine?
 

Thomaspark

Thread Starter
Joined
May 9, 2021
Messages
6
Intel I5 9600k
Asrock z390 phantom gaming sli/ac
16 GB Hyper x fury rgb ddr4
Msi gforce 1660 ti ventus oc
Thermaltake 700w smart 80 plus
Most basic corsair watercooler
Not a new build was working fine for a year the one day I shut it down now only way it will boot up is if the cpu plug is unplugged
Thank you for your reply. I vaught a new psu same type to see if it was the psu. I've taken everything out and tried out of the case to get the same result.
 

Thomaspark

Thread Starter
Joined
May 9, 2021
Messages
6
Can you provide more detail on the hardware you are working with?

What is the make and model of the following:

CPU?
Motherboard?
RAM?
Power Supply? Make, model and wattage
GPU? If a dedicated GPU is being used.

Is this a new build or a problem that has started with a previously working machine?
I replied in the post
 

Tanis

Shane
Joined
May 29, 2006
Messages
4,240
Can you download the ASRock Phantom Gaming Tuning utility from here

ASRock > Z390 Phantom Gaming SLI/ac

I am not familiar with the tool itself, but is there any form of Hardware monitor section? If there is can you screenshot it and post that here.

Can you also download and run the TSG System Info Utility (link below in my signature), copy and paste all the information into a reply.
 

crjdriver

Moderator
Joined
Jan 2, 2001
Messages
43,892
When I unplug the 12v atx cpu cable the pc will start up
You need to be very precise; when you say the system will start up, do you mean it will fully boot into the operating system OR do you mean you just see fans spin?
 

Thomaspark

Thread Starter
Joined
May 9, 2021
Messages
6
You need to be very precise; when you say the system will start up, do you mean it will fully boot into the operating system OR do you mean you just see fans spin?
Ok everything is plugged in like normal I press power button the fans spin an eight turn the nothing happens light on the mobo are on but the pc will not power up. If I disconnect the cpu plug the pc with start up fans and all running but of course it will not stay running cause the cpu plug is not connected it just loops
You need to be very precise; when you say the system will start up, do you mean it will fully boot into the operating system OR do you mean you just see fans spin?
The
You need to be very precise; when you say the system will start up, do you mean it will fully boot into the operating system OR do you mean you just see fans spin?
It wint boot the fan will turn an eight inch then nothing. That's with the cpu 12v plugged in. If I unplug the cpu and try to boot it will start fans LEDs etc all run. Just wont run cause the cpu is disconnected
 

Tanis

Shane
Joined
May 29, 2006
Messages
4,240
The 'twitching' fans is a common symptom of a failed PSU. If you have replaced the PSU with a new, known working unit and get the same I would be suspecting a motherboard issue.

However, what I would suggest is running through the steps in the second part of this sticky post:

Troubleshooting Guide for "Problem Builds" | Tech Support Guy (techguy.org)

Follow the guide from this point " You assembled the system, and it will not post " onwards.
 

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