# [SOLVED] PC turns itself off after a few seconds



## P0NYSLAYSTATION (Jul 20, 2011)

Hi, I installed a used motherboard a couple of months ago and up until now it has worked fine. A few days ago when I tried to turn my pc on after a few seconds it powered itself off again, though motherboard lights stayed on. I tested the pc with each component separately and found the problem did not occur if I took out the processor. Thinking the processor was the problem I replaced it with a new cpu, but the same problem occurred. Right now I'm thinking there's some kind of short in the motherboard across the cpu socket. Is there anything I can do about that or is the board just dead now?

My system specs:
ASUS Striker Extreme II
Intel Core 2 Quad Q89450 (the cpu when the problem started was a Q8400)
2 2GB Corsair XM3 DDR3
500GB SATA hard drive
ATI Radeon 6950HD
Corsair HX1000W
Windows 7 Ultimate 64-bit


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## Tyree (May 10, 2009)

*Re: PC turns itself off after a few seconds*

Your problem relates to a power issue. Possibly a short? Did you install one standoff, no more-no less, for every mounting hole in the Mobo?
Your PSU is top quality but it can't be ruled out as a possible problem.
Test on the bench and see if the problem persists.


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## P0NYSLAYSTATION (Jul 20, 2011)

*Re: PC turns itself off after a few seconds*

Hi thanks for the reply, there is a standoff on every mounting screw for the motherboard yes, sorry I'm not sure what you mean by test it on the bench?


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## Tyree (May 10, 2009)

*Re: PC turns itself off after a few seconds*

Bench Test
Remove EVERYTHING from the case.
Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity! 
Install the CPU and heat sink. 
Install 1 stick of RAM.
Install the video card and attach the power supply connection(s) to the card if your card needs it.
Connect the monitor to the video card.
Connect the power supply to the motherboard with both the 24pin main ATX Power connection and the separate 4 or 8 pin power connection.
Connect power to the power supply.
Do NOT connect ANYTHING else. Make sure you have the power connector on the CPU fan connected.
Use a small screwdriver to momentarily short the power switch connector on the motherboard. Consult your motherboard manual to find which two pins connect to your case's power switch. Then touch both pins with a screwdriver to complete the circuit and boot the system.

If all is well, it should power up and you should get a display. Then assemble the parts into the case and try again. If the system now fails to boot, you have a short in the case and need to recheck your motherboard standoffs.

If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective.


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## P0NYSLAYSTATION (Jul 20, 2011)

*Re: PC turns itself off after a few seconds*

Ok having done that it worked fine during the test and then stopped working again as soon as it went back in the case, so yeah I think you're right, it must be a short in the case. Irritatingly the standoffs are built into the case and in such a way that you can't use your own as well, so I guess that means I need a new case?


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## P0NYSLAYSTATION (Jul 20, 2011)

*Re: PC turns itself off after a few seconds*

Actually its fine I've managed to use perforated rubber over the tops of the standoffs to prevent contact, it seems to be working


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## Tyree (May 10, 2009)

The built in standoffs in OEM and cheap aftermarket cases will, as you have discovered, make contact with the Mobo and cause shorts. Thankfully you didn't do any damage.


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