Question PC won’t power once CPU_PWR is plugged in

[DXVIDM]

Hi all,

PC specs:
MOBO: PRO Z690-A
CPU: 13600k
GPU: AMD 7900XTX
PSU: Enermax Revolution D.F ERF850EWT

So my PC has been working fine for years, no issues etc. Today I wake up and go to turn it on, it boots for a couple seconds (doesnt display anything to monitor) then shuts off.
I try to turn it on again and the power button does literally nothing, no LED, no Fans, nothing.
So I strip the PC to find out the culprit and test the PSU on its own with the paperclip trick and it works just fine. I’ve tried to slowly place back cables into the PSU and find what the issue is and it turns out when I plug in my mobo 18 pin and 10 pin it turns on with a red cpu debug light, but then I try plugging in the cpu_pwr single 8pin cable and when I try to turn it on the PSU makes a click noise and nothing happens. No fans nothing.

Ive also took out the CPU and checked pins on board and they are all good, re-applied some thermal paste too and still the exact same issue.

Would a new CPU 8pin to 8pin work? Would a new PSU work? Is my CPU dead?


Help me pls!

 

[Lutfij]

So my PC has been working fine for years, no issues etc. Today I wake up and go to turn it on, it boots for a couple seconds (doesnt display anything to monitor) then shuts off.
+
PSU: Enermax Revolution D.F ERF850EWT
How old is your PSU?

So I strip the PC to find out the culprit and test the PSU on its own with the paperclip trick and it works just fine.
The paperclip test is flawed, it doesn't tell you how much power the PSU can effectively output to the entire system, only that it can power up.

Would a new CPU 8pin to 8pin work? Would a new PSU work? Is my CPU dead?
You will need to source(borrow, not buy) a reliably built PSU that can delivery 850W of power to the entire system, from a friend or neighbor in order to rule out your PSU being the root of the issue. You can drop your processor onto a known working motherboard and see if the issue persists.

How are you cooling your processor, btw?

 

[DXVIDM]

So my PC has been working fine for years, no issues etc. Today I wake up and go to turn it on, it boots for a couple seconds (doesnt display anything to monitor) then shuts off.
+
PSU: Enermax Revolution D.F ERF850EWT
How old is your PSU?

So I strip the PC to find out the culprit and test the PSU on its own with the paperclip trick and it works just fine.
The paperclip test is flawed, it doesn't tell you how much power the PSU can effectively output to the entire system, only that it can power up.

Would a new CPU 8pin to 8pin work? Would a new PSU work? Is my CPU dead?
You will need to source(borrow, not buy) a reliably built PSU that can delivery 850W of power to the entire system, from a friend or neighbor in order to rule out your PSU being the root of the issue. You can drop your processor onto a known working motherboard and see if the issue persists.

How are you cooling your processor, btw?

Arctic Freezer dual

 

[NibblePrancer]

So my PC has been working fine for years, no issues etc. Today I wake up and go to turn it on, it boots for a couple seconds (doesnt display anything to monitor) then shuts off.
+
PSU: Enermax Revolution D.F ERF850EWT
How old is your PSU?

So I strip the PC to find out the culprit and test the PSU on its own with the paperclip trick and it works just fine.
The paperclip test is flawed, it doesn't tell you how much power the PSU can effectively output to the entire system, only that it can power up.

Would a new CPU 8pin to 8pin work? Would a new PSU work? Is my CPU dead?
You will need to source(borrow, not buy) a reliably built PSU that can delivery 850W of power to the entire system, from a friend or neighbor in order to rule out your PSU being the root of the issue. You can drop your processor onto a known working motherboard and see if the issue persists.

How are you cooling your processor, btw?

It sounds like you’ve done some solid troubleshooting so far, but let’s break this down step by step:

1. PSU Paperclip Test: As you mentioned, the paperclip test only confirms that the PSU can power on—it doesn't test its ability to deliver stable power under load. If the PSU is aging (and Enermax PSUs, while good, can degrade over time), it might not be supplying consistent power to the CPU or GPU. Borrowing a known working PSU to test your system is definitely the next logical step.
2. CPU 8-pin Cable: If the PSU is fine but your 8-pin CPU cable is damaged or not seated properly, replacing it might resolve the issue. However, this is less common unless you’ve noticed physical wear or damage.
3. CPU or Motherboard: It’s less likely that the CPU itself is dead—modern processors are pretty resilient. However, a failing motherboard could cause symptoms like these, such as insufficient power delivery or a short circuit. Testing the CPU on a different motherboard is a good way to rule this out.
4. Cooling: If your processor isn’t being cooled properly (e.g., a detached or failing cooler), the system might shut down immediately to protect the CPU. Double-check your cooler’s mounting and fan operation.

Suggestions:

• Test the system with a different PSU.
• Inspect your motherboard for blown capacitors or burn marks.
• Reseat the CPU and cooler, and reapply thermal paste if needed.
• If you can, test the CPU on a different motherboard or test your motherboard with another CPU.

Good luck, and let us know what you find!