Power supply issue? troubleshooting..

Tretik

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Jun 5, 2013
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10,510
Hi,

I am trying to figure out what's going on with my desktop PC. When I press the shut down key in Windows 7, the OS shuts down, however, the PC does not power off. The fans are going and the green light is still on. The only way to power down the PC is to hit the switch off in the back (near power cord). When I hit it back on - the computer powers on without me hitting the power button.

Is that an issue with my power supply?
Help please.
 
You will need to go into BIOS and disable boot after AC power loss to stop it from turning back on after you hit the power switch on the PSU, most systems have this disabled by default, some don't.

The fans still running may be caused by how the system is shutting down, are you doing a full shut down or is it hibernating? Some systems don't turn all the way off when in hibernate, my system used to end up with the system fans running when in hibernate.
 

Tretik

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Jun 5, 2013
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Thank you for your suggestion. Same thing happens. I enter safe mode, try to shut down the computer. OS shuts down but the power does not go off. OS boots fine when I press the power button.
So OS shuts down fine and boots up fine, but for some reason there is some kind of disconnect and power supply is not told to be turned off when I shut the computer down.
 

Tretik

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Jun 5, 2013
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10,510


I went into BIOS and it was disabled. The issue is that I did not change any settings in BIOS and I doubt it changed them itself. I did install some graphic card updates recently but that's it.
I do click "shut down" and not "hibernate" when I am shutting it down.

By the way my system is:

ASUS P8Z68-V LX (BIOS v. 3506)
i5-2400 @ 3.1 Ghz LGA 1155 95W Quad-Core
16 gb RAM (4x4) Corsair Vengeance
ASUS GTX550 TI 1 gb
PSU DIABLOTEK|775W PSUL775 R
Windows 7 Ultimate Service Pack 1
 


The reason I suggested that is to determine if there was any rogue driver, process or application that may be causing a problem during a normal boot.

The only other suggestion I have is to temporarily borrow a different power supply unit for troubleshooting purposes and see if the problem still happens. If the problem still occurs with a different PSU then I would suspect a problem with the motherboard.
 

Tretik

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Jun 5, 2013
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10,510

So it seems like you are thinking it is more of a hardware issue, right?
 

Tretik

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Jun 5, 2013
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I updated BIOS. Still same issue persists.
If it is a PSU issue, should I get a more powerful PSU then? I am just trying to figure out what went wrong - I assembled my system only a year ago and everything was fine until a couple of days ago
 


For a system using a single GeForce GTX 550 Ti graphics card NVIDIA specifies a minimum of a 400 Watt or greater system power supply that has a maximum combined +12 Volt continuous current rating of 24 Amps or greater and that has at least one 6-pin PCI Express supplementary power connector.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most important factor.

Overclocking of the CPU and/or GPU(s) may require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.

The Diablotek UL Series 775W (PSUL775), with its maximum combined +12 Volt continuous current rating of 60 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is way more than sufficient to power your system configuration with a single GeForce GTX 550 Ti graphics card.

Your problem is not a lack of power capacity. It's more likely a problem with the quality of the power supply unit itself.

Buy quality, not quantity!
 

Tretik

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Jun 5, 2013
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Thanks for advice! Uh, I actually spent some time last year picking the PSU. It had good reviews. I guess it's time to invest in more quality. Would you recommend a specific PSU for me? What about this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139011 Thank you!
 


The Corsair HX850 is fine if you're planning on buying two GeForce GTX 780 or 770 cards to run them in 2-way SLI mode.

This one is way more than enough to power your current system configuration:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151124
 

Tretik

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Jun 5, 2013
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10,510

Thank you for the info! I'll update you whether the new PSU fixes the issue
 

Tretik

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Jun 5, 2013
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10,510


The problem was solved by purchasing a new PSU. Thanks!