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  1. #1
    Join Date
    Oct 2012

    Exclamation Corsair hx750 power supply

    Hi ive recently built my first computer and when i finally turned it on the computer and all components turn on and then suddenly turn off. I don't have any operating system installed but the computer just wont stay on?

  2. #2
    Member abseh1's Avatar
    Join Date
    Jul 2008
    Tampa Bay
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    Woo-ow on a new build it could be many things

    This is really a hands on fix....hard to say in a posted forum

    Just go step by step in your install (trace your steps)....the fan power lead on the PCU is designated and if not connected correctly...could fry your will also, immediately shutdown at a certain temp...that may be an issue

    It could also possibly be your Motherboard....or psu etc

    It may not be the PSU. ...The Corsair is an excellent PSU....but not perfect

    It may not be the PSU. ...if so use your warranty

    I'd open up the tower use a multi-meter and read to see if there is power going to the board from the PSU. If there is power then it could easily be the board.

    Just guess guess best I can do...sorry

    If you give the mobo info maybe we can advise better...there are 4 pin and 8 pin power connections etc
    Last edited by abseh1; 12-12-2012 at 08:20 PM.
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  3. #3
    Member Digerati's Avatar
    Join Date
    Dec 2008
    Nebraska, USA


    I am not in favor of sticking sharp, highly conductive meter probes into the heart of the computer. If you do not know where to stick it, you can easily short out something important, or slip and slice through several traces on the board. Not to mention potential ESD damage. Plus, you would need to know what voltages to look for. There are 3 different voltages, all essential. You can simply look to see if the CPU fans spins (at least for a second) when you first power up and that will tell you if the motherboard has some power - assuming your board does not have LED indicator lights on it. Or you could use a PSU Tester. While not conclusive, they are pretty good indicators of PSU status - without risk of collateral damage.

    Is the CPU heatsink fan securely mounted with a good layer (or OEM pad) of TIM (thermal interface material)?
    Are you sure you attached all the power cables to the motherboard (most boards take two or three) and any separate cables to the graphics card (if required)?
    Are you 200% sure there are no extra standoffs under the motherboard? Note cases are designed to support 1000s of boards so there typically are several more standoff mounting points than there are corresponding motherboard mounting points.
    Any beeps?
    Is the CPU fan power connector attached to the motherboard's CPU fan power header? (Header = pin connector)
    Did you observe proper ESD precautions while handling sensitive parts and assembly? This is particularly important when handling CPUs, RAM modules, and add-in cards.

    You may need to take everything out of the case and put the motherboard on a hard, non-conductive surface. I use a big breadboard. Then assemble the computer outside the case to see if it works there. If it does, check the standoffs again, or for any other foreign object.

    I agree that you may have gotten a bad PSU. While Corsair happens to be my preferred brand (because of their high quality), until Man can create perfection 100% of the time, there will be some failures. So swapping in another known good supply may be worth a try.
    Bill (AFE7Ret)
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