Bad power supplies, or evil motherboard?

  1. Posts : 1

    Bad power supplies, or evil motherboard?

    TL;DR: Power supply was working, put computer to sleep, power supply went dead. New power supply was working, did not put computer to sleep, power supply went dead. Is the problem two faulty power supplies or a motherboard from hell?

    Over the past week I've run into a problem with a couple of power supply units, or potentially the motherboard. The best way to describe this problem is to describe the chain of events in order:

    - Computer is functioning normally for years. I put the computer into sleep mode and go to bed.
    - The next morning the computer will not power on.
    - The power supply, NZXT HALE90, makes it's usual "click" sound, but no power.
    - There is also no power when attempting to power on through the motherboard's power button.
    - The motherboard LED light does go on when the power supply is switched to "on".
    - The power supply is removed, tested with multimeter/paperclip trick: No power.
    - A new power supply is purchased, a Corsair gold-rated unit.
    - The power supply is connected to the computer. It powers on successfully and the computer works.
    - The power supply had something like a "hiccup" when powering on. Powered on, then off, then on again.
    - This also happened to my first power supply (HALE90) the first few times using it back in 2013.
    - Computer continues to function normally for the next couple hours. No problems to report during usage.
    - I fall asleep with the computer still on. Upon waking up, the computer is now off. The monitor is still on.
    - The computer will not turn on. The fan will spin for half a second, but no power.
    - As before, the motherboard LED goes on when the power supply is switched to "on".
    - The power supply is removed, tested with multimeter/paperclip trick: Power cuts within half a second.

    And that's where I am right now.

    The case is a CoolerMaster HAF, the motherboard is an ASUS P8Z68 model, the video card is a GTX 580.

    The computer is connected to a surge protector that still tests as "protected". There were no power outages during this time, the monitor itself stayed on in the second scenario, and no other electronics connected to the outlet are showing any effects.

    From my perspective there are two possibilities here.
    1) My original power supply simply gave out, and I just happened to purchase a faulty power supply that only worked for a few hours.
    2) My motherboard or some other component is malfunctioning in a way in which the power supply is getting damaged.

    My intuition is of course the first option, but I've been unable to find enough information on my own to rule out the second option. Is that even possible? Is there another option I'm missing? I've now purchased a 3rd power supply. My fear is that if something is wrong with the computer I could burn out the new power supply.

    What explains all this and what should I do? Thanks in advance.
    Last edited by TunaSalad9; 27 Sep 2017 at 13:23. Reason: formatting broke
      My Computer

  2. Caledon Ken's Avatar
    Posts : 24,184
    Windows 10 Pro x64 Version 2004

    Hi TunaSalad9. Welcome to the TenForums @TunaSalad9

    My intuition is motherboard. You said when you paper clipped second PSU it turns on.

    I would disassemble and re-assemble making sure MB screws aren't shorting, cables connections are pull apart and reseated. Remove and reseat expansion cards.

    Inspect MB, particularly capacitors, any mis-shaped?

    I would also not expose my data drive during these tests. Power can be quite destructive and while it hasn't fried a drive you just never know.

    Low voltage condition on your lines, should be 120v slides to 109V, are hard for you to see but power in North America can fluctuate. Very trying on sensitive devices. I use a UPS to compensate for this and full on blips.

    Any chance there is a large load on same house circuit?

    Assuming your BIOS is running defaults you may wish to remove coin battery and reset BIOS. If you've modified you need to re-apply changes. Know what you've changed.

    When you place back together only have installed what you need to boot. When you boot are you getting any beeps?

    Other members will likely have other ideas.

      My Computer

  3. Steve C's Avatar
    Posts : 6,286
    Windows 10 Pro 64 bit

    Do both PSUs fail the paperclip test with nothing else connected to the PSU? If so, then you have two bad PSUs (unlucky!) or a problem with your power lead or mains socket - trace back through these. If the PSU passes the paperclip test but fails under load then suspect the motherboard or other connected peripherals taking an excess load and shutting off the PSU. Note there are handshaking signals between the motherboard and PSU which can cause the PSU not to turn on if the motherboard is faulty.
      My Computers


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