New Build hit power button, powers up for half a sec and powers down

[hialeah05]

Hey all,
So I was helping my roomie with his first gaming build and we decided on these parts:

Mobo: ASRock P67 PRO3 (B3)
CPU: Intel i3 2120
GPU: XFX Radeon HD 6870 1GB
PSU: Raidmax 630W pseudomodular
RAM: G.SKILL Sniper 8GB (2 x 4GB) DDR3 1333
HDD: seagate barracuda SATA 6 GB/s 500GB
Optical: samsung Blu-ray burner

We put it all in the case, crossed our fingers and pressed the power button. Then we saw a flash of light come out the PSU and heard a fan move slightly. We pressed the power button again and got nothing this time.

So we opened the case and checked all the power connections and RAM to make sure it was in. Then we fired it up again while the case was open. This time we saw the power supply lights turn on and the PSU fan and CPU fan start to rev up (which we assume happened the inital try but just didn't get to see it). However it only got power for about a half a second and then it all shut down.

I'd normally try a different PSU in the build but I have no other PSU that can power the build with it's connections. Any ideas? Should I try to take something out to rev it up? Like run with less parts or something. (the GPU is needed for video output)

I've got no idea which part is the culprit as I've never seen the PSU give power to only shut off before. In my experience when the PSU gives out it never gives any sign of life on boot. My only idea is maybe the Power switch header is connected backwards, but would it cause this pattern of behavior? Any help is appreciated, thanks.

[RickyTick]

Try booting with only one stick of ram installed. Check the manual to verify which DIMM slot to install the ram.

Do you have the proper 8-pin cpu connector used?

[john123]

You could check if there any loose parts connections. GPU, Ram, Processors, hard drive, PSU cables.

[ThatOneGuy]

Although I know you do not have another power supply problem to use, it seems like that is the most likely culprit. If it is still with warranty, try going to the manufacturer's website and submitting an RMA to do an exchange.

[ThatOneGuy]

I had a very similar problem. As noted in my first post I thought my problem was the power supply I was wrong. My problem ended up being a motherboard short due to incorrect install.

If the case was supplied with standoffs (usually brass pieces with a screw on one end and the other side a screw can be screwed into), make sure the flat screw holes have utilize the standoffs.

Your case could be built one of three ways: all of the screw holes are raised, some of the screw holes are raised and some are flat, or all are flat.
If its case 1, then just screw in all of the screws provided once the motherboard is placed.
If it's case 2 than you are usually supplied 3 standoffs, screw those in the the flat holes, than place the motherboard and screw in the screws into the holes, and all should fit normally.
For case 3 place all the standoffs, place the motherboard than screw in the screws, and all should be good to go.

This solution is just another thought. This was my culprit in a very similar situation as yours.
For case 3 screw in all standoffs, place the motherboard than screw in the screws.