Check the PSU ?

I am planning to change the PSU, but I was thinking since this is a ATX supply, could something on the motherboard be bad to instruct the PSU to start over and over again?

Agreed, sounds like the PSU has failed. Either that or the power button has got jammed, which is unlikely.

I'll throw an alternative out the, could be a grounding issue, I had a similar issue a while back. I'm made sure the PSU and motherboard were well grounded to the chassis and the problem went away.

It's nosferatu.

Ampera wrote:

It's nosferatu.

I agree with the rest on this matter. This is exactly what happened last time I had a power supply unit fail on me. Except in my case it melted the power cord to the PSU.

vladstamate wrote:

So I have this P4 machine that the other day when I went into my office noticed that it was starting and stopping. I am just looking at it and it turns itself on and after 5 or so seconds shuts down then after 5 seconds or so it starts again. If I power off from the button on the back of the PSU then it does not start again.

Starting it from the front has no impact, as in it will shut down after 5 seconds then proceed to start again and stop again, etc.

What can be the faulty component?

Are you sure it's not 4 seconds instead of 5 seconds?
I'd first replace the PSU, but reseating everything might be a good idea also.
No beeps?

Tetrium wrote:

Are you sure it's not 4 seconds instead of 5 seconds? I'd first replace the PSU, but reseating everything might be a good idea a […]
Show full quote

vladstamate wrote:

So I have this P4 machine that the other day when I went into my office noticed that it was starting and stopping. I am just looking at it and it turns itself on and after 5 or so seconds shuts down then after 5 seconds or so it starts again. If I power off from the button on the back of the PSU then it does not start again.

Starting it from the front has no impact, as in it will shut down after 5 seconds then proceed to start again and stop again, etc.

What can be the faulty component?

Are you sure it's not 4 seconds instead of 5 seconds?
I'd first replace the PSU, but reseating everything might be a good idea also.
No beeps?

Just had a thought, it might be a shorted PWR pin/switch/button. Some systems won't respond to a shut down button press until they've entered the main post phase which on most PCs takes about 5 seconds. That would cause the behavior described but this is extremely unlikely. I highly recommend OP checks his power supply.

TheAbandonwareGuy wrote:

Tetrium wrote:

Are you sure it's not 4 seconds instead of 5 seconds? I'd first replace the PSU, but reseating everything might be a good idea a […]
Show full quote

vladstamate wrote:

So I have this P4 machine that the other day when I went into my office noticed that it was starting and stopping. I am just looking at it and it turns itself on and after 5 or so seconds shuts down then after 5 seconds or so it starts again. If I power off from the button on the back of the PSU then it does not start again.

Starting it from the front has no impact, as in it will shut down after 5 seconds then proceed to start again and stop again, etc.

What can be the faulty component?

Are you sure it's not 4 seconds instead of 5 seconds?
I'd first replace the PSU, but reseating everything might be a good idea also.
No beeps?

Just had a thought, it might be a shorted PWR pin/switch/button. Some systems won't respond to a shut down button press until they've entered the main post phase which on most PCs takes about 5 seconds. That would cause the behavior described but this is extremely unlikely. I highly recommend OP checks his power supply.

I have had similar start restart issues like that before. Turned out to be a bad tiny switch. Tossed it and got another one.

Tetrium wrote:

Are you sure it's not 4 seconds instead of 5 seconds?
I'd first replace the PSU, but reseating everything might be a good idea also.
No beeps?

I got it working. I took out the power supply, opened it to visually inspect it (nothing wrong), then put it back together and reconnected all power cables. Now the computer is behaving again. Could either have been temporary bad power switch contact or some cables were not properly inserted.

Thank you all for the advice and help.

vladstamate wrote:

Tetrium wrote:

Are you sure it's not 4 seconds instead of 5 seconds?
I'd first replace the PSU, but reseating everything might be a good idea also.
No beeps?

I got it working. I took out the power supply, opened it to visually inspect it (nothing wrong), then put it back together and reconnected all power cables. Now the computer is behaving again. Could either have been temporary bad power switch contact or some cables were not properly inserted.

Thank you all for the advice and help.

yw, glad you got it going again 😀
Sometimes something ought to not work or not change anything regarding functionality, but still does, defying all logic. It's weird, but sometimes things works that way 😜