Shuts Off on Bootup *Fixed*

[clamum]

I have a computer that when you press the power button: the CPU fan, P/S fan, and rear fan all start up for a second and then the computer shuts off. That's all that happens. I'm not sure what is wrong, any ideas or suggestions? Thanks!

EDIT: Problem solved, it was the power supply unit

 

[maXroOt]

i had that same problem before, my MB was touching part of the case, so it was shorting out. it acted exactly as how u described. i bought some rubber o-rings (can get at home depot for a buck or 2) and attached them between the case and motherboard. worked fine

 

[duragezic]

Originally posted by: maXroOt
i had that same problem before, my MB was touching part of the case, so it was shorting out. it acted exactly as how u described. i bought some rubber o-rings (can get at home depot for a buck or 2) and attached them between the case and motherboard. worked fine

Attached them below where the mobo screws onto the case?

Hopefully that'll work, thanks!

 

[clamum]

Oops last post was me. Brother was logged in.

 

[Jojo7]

Is this a new computer you just built?

Is the heatsink installed correctly? It could be overheating and shutting itself off.

Also, I had the same problem on my amd system. It turned out to be the motherboard battery. Don't ask me why. I replaced it and it hasn't powered off since. My motherboard that was having the problem was an epox 8k3a.
Does windows always display the correct time after you turn your pc off for a while, then back on?

 

[mechBgon]

Originally posted by: Jojo7
Is this a new computer you just built?

Is the heatsink installed correctly? It could be overheating and shutting itself off.

Also, I had the same problem on my amd system. It turned out to be the motherboard battery. Don't ask me why. I replaced it and it hasn't powered off since. My motherboard that was having the problem was an epox 8k3a.
Does windows always display the correct time after you turn your pc off for a while, then back on?

Yeah, check your heatsink orientation if it's a Socket-A CPU (Athlon/Duron). Here's the idea: photo and here's the wrong way: photo 2 Having the heatsink backwards prevents the heatsink from making square contact with the CPU core, and triggers a near-instant overheat and emergency shutdown.

 

[clamum]

Nope it's not a new computer. Somewhat recent though... I believe the processor is an 800 (Intel). It's my girlfriend's actually. It has been working just fine and then one time she goes to start it and this happens.

Also, I don't believe it's the motherboard shorting out because I tried the rubber o-ring solution and that didn't work. After that I took the motherboard out of the case completely so it couldn't possibly be touching any metal and hooked it up that way, and it still didn't work.

So I'm not sure what's wrong... Maybe power supply unit? And yeah the heatsink is seated correctly, as it has worked in the past.

I'm going to try replacing the motherboard battery with another spare one I have from a different computer and see if that works...

 

[mechBgon]

Sounds like you already took some good troubleshooting steps, then. Did you happen to have tried it with the drives unplugged from both the PSU and the motherboard? If it started but shut down after about five seconds, then I'd also suggest maybe the power button is having a mechanical problem and remaining "pushed" internally, but it sounds like it shuts off faster than that.

If it's got a slot-1-style CPU, also re-seat the CPU in case it got jarred loose a little. If all else fails, try stripping the mobo bare (not even the CPU itself) and then start it that way. The power supply's fan should start running and stay running, if the motherboard is healthy (although it may let out a fussilade of beep codes). If that doesn't work then you can try it with another PSU to judge whether the PSU is dead. Good luck with the troubleshooting

 

[clamum]

Originally posted by: mechBgon
Sounds like you already took some good troubleshooting steps, then. Did you happen to have tried it with the drives unplugged from both the PSU and the motherboard? If it started but shut down after about five seconds, then I'd also suggest maybe the power button is having a mechanical problem and remaining "pushed" internally, but it sounds like it shuts off faster than that.

If it's got a slot-1-style CPU, also re-seat the CPU in case it got jarred loose a little. If all else fails, try stripping the mobo bare (not even the CPU itself) and then start it that way. The power supply's fan should start running and stay running, if the motherboard is healthy (although it may let out a fussilade of beep codes). If that doesn't work then you can try it with another PSU to judge whether the PSU is dead. Good luck with the troubleshooting

Ah didn't know it would start up without the CPU attached! Anyways I tried what you said and started it up bare with just the mobo and RAM in it and it still did the same thing. It's definately under 5 seconds, probably about 1/2 a second actually. The fans just start to move and then it shuts off with no beeps or anything. I wish I had another PSU to test it with! But it sounds like that's where the fault lies...

 

[clamum]

Alright I got it, it was the power supply unit. I took the P/S out of this computer and tried it, it booted up fine. At least I learned some new troubleshooting procedures, hehe.

Thanks for all your help to those who replied.

 

[mechBgon]

awriiight :gift: