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PC won't power up

Discussion in 'Specific Hardware Issues' started by Falling Sloth, Sep 25, 2019.

  1. Falling Sloth

    Falling Sloth

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    I have recently installed a new USB controller card (PCIe) and now my PC won't power up, even after removing it. The lights on the motherboard come on, but the power button does nothing (the one on the case or the one on the motherboard itself).

    I used a jumper to test the PSU (it works), I've tried clearing CMOS (no change), I've removed the new card but it still won't turn on. Anyone have any ideas?
     
  2. Tony D

    Tony D Administrator Administrator

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    Hello and welcome Falling Sloth. What else is there to do? Something happened.

    Remove any unneeded expansion cards and drives, including the boot drive. See if that helps.

    I see you tested the PSU to see if the machine would power up. When you do that, you need to check all the voltage lines to make sure they are all good. Don't rely on a fan spinning up to indicate the PSU is good.

    Remove the RAM and see if the machine makes any beep tones complaining about not having any RAM.
     
  3. Seth Anthony

    Seth Anthony Registered Members

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    Further to what Tony said, I've never understood the jumper psu test method, as it's not testing the rails, and it's not under load.
     
  4. Falling Sloth

    Falling Sloth

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    To clarify, when I jumpered the 24 pin connector on the PSU it was still connected to everything else in the system. The drives span up, the case lights came on and the pump started going so there was some load and it seems to be fine.

    I'll try removing the ram and the other expansion cards in the morning, see if it helps and report back.
     
  5. Seth Anthony

    Seth Anthony Registered Members

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    So you don't have a power up issue if the drives are spinning, but rather a no display issue. Correct?
     
  6. Tony D

    Tony D Administrator Administrator

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    When you jumpered the 24 pin connector, how did you do it? I typically shove a pin into the PSU/Board connector while they are mated. I shove the pin into the green wire pin and take that to ground via a resistor. However you can short it out to ground directly.

    You’re essentially micking the board telling the PSU to “Start Up”. You’re correct in saying that the PSU is under load. You still need to check all the voltages to verify they come up to spec.

    If the voltages are correct, then the board is not telling the PSU to start.
     
  7. Seth Anthony

    Seth Anthony Registered Members

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    Ah nevermind, I see what you mean now by the drives spinning up.
     
  8. Falling Sloth

    Falling Sloth

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    I used one of these https://www.ekwb.com/shop/ek-atx-bridging-plug-24-pin, it came with the pump.

    I took everything out of the motherboard and nothing. I don't have my multimeter right now, but if the PSU voltages do check out what are the alternatives? A dead motherboard?
     
  9. Seth Anthony

    Seth Anthony Registered Members

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    To be clear, what exactly is happening when you press the power button now?

    Do the fans come on? Do the drive(s) spin up? Does anything appear on the monitor?


    It seems to me that the board got cracked on insertion of the card and/or the card was defective and shorted out causing a blown mobo or psu. Of those 2, I would suspect the mobo.
     
  10. Tony D

    Tony D Administrator Administrator

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    I'm not sure what that gadget does. It looks like it plugs into the PSU, but not the board. Is this correct? If so, the PSU is not presented with the load of the board.

    My gut feel is it's a board problem. Answer Seth's questions. I'll be away for most of the day going forward.
     
  11. Seth Anthony

    Seth Anthony Registered Members

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    I don't know what that gadget does either. What I do know, is that it's not under load, doesn't check the rail voltages, doesn't check Amperage, and doesn't check the cpu connector power.

    Sloth, do you have an extra psu kicking around to try out?
     
    Last edited: Sep 26, 2019
  12. Falling Sloth

    Falling Sloth

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    It shorts the PS-ON pin to ground, used for running a pump without running the whole system for filling the loop.

    Still not getting anything from the motherboard, the lights are on but it's not powering up at all. The usb ports on the back are still powered, but it won't even try to POST.

    I might have an old PSU in a cupboard, I'll try that later.
     
  13. Seth Anthony

    Seth Anthony Registered Members

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    In one way or another if the psu is ruled out as the problem, then the mobo is causing the issue. It's either cracked, a board component(s) is blown, or due to the pressure of installing the card, the board is making contact with ground.

    One long shot is unplugging the power, pulling the battery, and holding down the power button for around 30 seconds. Put the battery back in and see what happens.

    Also as a long shot, re-seat your cpu power connector.
     
    allheart55 (Cindy E) and Tony D like this.
: no power, no post

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