CPU fan keeps turning on and off

deepankarchatterjee

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Dec 5, 2011
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When I use to put 'on' the switch next to my power plug (without still having pressed the power button of my CPU cabinet) I use to see the CPU and cabinet fans run for a second and then stop. Next I press the power button on my CPU cabinet and my PC use to run fine. This was a normal startup sequence.

Now what has started is that as I put 'on' the switch next to my power plug (without still having pressed the power button of my CPU cabinet) I find the CPU and the cabinet fans run for a second, then stop, then again run for a second and stop and this sequence goes on.

If I press the power button on my CPU cabinet, nothing happens that is, no system boot up.

I doubt the power supply as the culprit. Help me diagnosis and resolution.

Regards

Deepankar
 
the power supply is most likely the problem. the fan spinup when you turn the power supply on and it initially supplies power to the board. the power supply seems to just be turning itself off and on now. I suppose it could be your motherboard as well but the PSU is easier to test