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Computer Shuts Down after about 15 - 20 Seconds

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Computer Shuts Down after about 15 - 20 Seconds

jimecc
I'm at my wits end with this computer. It's now got a brand new motherboard, but still doing the same thing, i.e., powers off after a few seconds.I have checked all the hardware by using another computer and everything works fine, to include changing out the power pack as well as the memory. I did discover that if I remove the memory from the MB it doesn't shut down until you manually shut it down. I discovered this with the old MB so I thought that the MB was bad and replaced it. Could the CPU be bad? I really hate to replace it only to discover that I have the same problem. Any help/suggestions will be appreciated. Thanks - Jim
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    Fan

    TheChas

    Have you tried a different CPU Fan?

    Does the CPU fan spin free when the power is off?

    Many motherboards are set to shut the system off if the CPU fan is not running.

    Even if the fan spins, it could be running too slow, or the tach output could be bad.

    Based on what you have swapped out, I would suspect the CPU.

    If you have any doubts about the existing CPU fan, replace it at the same time. At a minimum, you need to clean off the CPU and heatsink and apply fresh thermal compound anytime you remove the heatsink.

    Aside from swapping out the CPU, a POST card might tell you why the PC is shutting down.

    While your at it, you might buy 2 CPUs since it sounds like you have enough parts to build another system.

    Chas

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    zlitocook

    Does it get past the post, does it show on the monitor? Do you see the black screen with white letters that show the Bios, memory and drives?
    If you remove the memory it should not even boot, you should get a series of beeps.
    I would remove all cables to hard drives, DVD drives and just boot to the basic system. All you need is video, memory, cpu, keyboard and mouse. To see if it gets past them, if it does then it could be one of your add on's like the dvd or video card.

  • +
    0 Votes

    Fan

    TheChas

    Have you tried a different CPU Fan?

    Does the CPU fan spin free when the power is off?

    Many motherboards are set to shut the system off if the CPU fan is not running.

    Even if the fan spins, it could be running too slow, or the tach output could be bad.

    Based on what you have swapped out, I would suspect the CPU.

    If you have any doubts about the existing CPU fan, replace it at the same time. At a minimum, you need to clean off the CPU and heatsink and apply fresh thermal compound anytime you remove the heatsink.

    Aside from swapping out the CPU, a POST card might tell you why the PC is shutting down.

    While your at it, you might buy 2 CPUs since it sounds like you have enough parts to build another system.

    Chas

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    0 Votes
    zlitocook

    Does it get past the post, does it show on the monitor? Do you see the black screen with white letters that show the Bios, memory and drives?
    If you remove the memory it should not even boot, you should get a series of beeps.
    I would remove all cables to hard drives, DVD drives and just boot to the basic system. All you need is video, memory, cpu, keyboard and mouse. To see if it gets past them, if it does then it could be one of your add on's like the dvd or video card.