When disconnect ATX12V1, CPU fan starts spinning

[wowkin2000]

My PC suddenly stopped and I got the message on the screen, "fan

failed". I replaced my PSU. I turned on my PC, but nothing happened.

I opened the case. I disconnected and reconnected everything but I

forgot to connect ATX12V1. The CPU fan starts spinning. When I

connected ATX12V1 again, the CPU fan stopped spinning.

Is my motherboard or CPU, or both dead?

How can I fix this problem to keep the software on the hard drive

running without reinstall them again?

p.s. whenever I turn on my PC, the CPU fan starts to spin (but not yet

to spin) and stop.

 

[rolli59]

I would suspect the motherboard. Sounds like there is problem on the motherboard with the power circuitry from the ATX connector.

 

[wowkin2000]

I would suspect the motherboard. Sounds like there is problem on the motherboard with the power circuitry from the ATX connector.

I have editing some videos and not yet finish. What is the best way to make my PC /hard drive work again. So I can continue do my video editing.

Someone told me. I can replace the motherboard with an identical one. Also, if the CPU is bad, too, replace it. But my PC is 5 years old. It is not easy to get the same model of motherboard and CPU that I used before.

Is there the only way? Reinstall all the software then continue to do what I do before?

 

[rolli59]

Ebay can be a source for older hardware. My best guess is that it is your motherboard. You can upgrade to a newer system just get a new HDD drive for your OS and install your old drive as data drive to recover all of your documents and files. You would though have to reinstall all the programs.

 

[wowkin2000]

Best answer selected by wowkin2000.

 

[wowkin2000]

I would suspect the motherboard. Sounds like there is problem on the motherboard with the power circuitry from the ATX connector.

Do you have any idea why the CPU's fan starts spinning when I disconnect ATX12V1 (power CPU's fan)?

 

[rolli59]

Not really all I know is that the CPU gets its power from the ATX12v1 the fan gets it from the other circuitry (20-24 main connector). Apparently there is some flaw that triggers a safety for when the ATX is connected. After reading your post again, did you reset BIOS after trying to start up without the ATX connector?

 

[wowkin2000]

Not really all I know is that the CPU gets its power from the ATX12v1 the fan gets it from the other circuitry (20-24 main connector). Apparently there is some flaw that triggers a safety for when the ATX is connected. After reading your post again, did you reset BIOS after trying to start up without the ATX connector?

Yes, I did. Same thing happened.

It is very strange. When connect to the ATX12v1, it means power up the CPU. Then the power supply is automatically stopped by the circuit on the motherboard. If disconnect it (no power to CPU), the power supply can go through the circuit, and power up the whole motherboard except the CPU.