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PC Only powering up by PSU Switch, but turns off after a few Seconds

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  • Homebuilt
  • Systems
Last response: in Systems
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June 14, 2012 2:30:44 PM

Okay So i brought this i7 Gaming PC From Ebay, the seller has a pretty solid Selling History so i do not doubt him, I got this today and i installed my copy of windows Ultimate then also Installed the motherboard drivers from disk and also the Graphic card drivers from disk all was going well intill my wife decided to try and switch from the vga cable to the hdmi cable while the pc was still running then pressed the power button to turn it off, now after this the power button no longer clicks like it should when pressing it to turn on and the only way to power the pc up is the flip the PSU power switch off and on and even this doesnt always work but once i get the pc to finally power up as soon as you hear the hard drive kicking in it just powers off, i have spoken to the seller and he said he tested it for 5 hours non stop when he sent it but it could be the PSU, does anyone know how i could fix this without spending more money?

More about : powering psu switch turns seconds

June 14, 2012 3:12:33 PM

I don't see how a well built system can fail after clicking the power button once to turn it off. Do you have a link or know what components are in it?
a b B Homebuilt system
June 14, 2012 3:22:39 PM

My guess is the swap of video cables is not related.

What you describe sounds like the pushbutton front-panel power switch is stuck pressed in. It is a momentary-contact switch. In NORMAL operation, one short push will cause the mobo to start up. After that, one long hold-it-in-for-5-seconds "push" will cause the mobo to shut down without any instructions from Windows. So, if that switch is permanently closed (pushed in), it will never give the mobo the start-up signal, and that's why you have to use the PSU switch to get action. But then, as soon as the mobo gets going, it finds the switch if being held in, so it shuts down!

To test, try two possibles.

1. Disconnect power, open the case, and disconnect the leads for this on/off switch from the Front Panel terminal block on the mobo, so there is no connection there. In this state, you should have to use the PSU switch on the back to start up, but it should keep running until you shut down normally.

2. Again at that mobo terminal block, move the leads for the Reset switch from their normal location to the two pins for the on/off switch. The front-panel Reset pushbutton is exactly the same type of switch. In this state, you should be able to use the Reset button as a perfectly normal On/Off pushbutton.

If those tests confirm that the mobo is just fine, then you have a problem to fix with the On/Off pushbutton. Simplest solution is to leave Test #2 in place - let the reset button continue to be your On/Off button, and live with no Reset. Best solution is to fix or replace the On/Off pushbutton. For starters, check it carefully in case a bit of junk got into it and is jamming it so it can't pop back out. If all else fails, ANY momentary-contact pushbutton can be used for this - it does not need extra heavy electrical ratings or anything. Just find whatever fits or can be mounted somewhere handy.
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a b B Homebuilt system
June 14, 2012 3:32:08 PM

B.A. to Paperdoc, except in #1 if there's no power switch attached, you can't start the PC with the PSU switch, you have to start it by momentarily shorting the power switch pins with a screwdriver, paperclip, or similar metal object. Obviously, a permanent replacement as described in #2 is best.
If you're lucky, the switch will just be stuck down, and a tap or two will free it.
a b B Homebuilt system
June 15, 2012 1:35:59 AM

jtt283 is completely correct - I goofed! To get it to start, you'd have to momentarily short together the two pins that the switch wires were pulled from.
!