Computer died this morning, need help determining which part to replace.

kevinstyles

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Dec 30, 2014
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Hello and Merry Christmas. I went to wake my computer up this morning, the mouse lit up and so did the motherboard and fans for half a second and then black. I went to turn the power on again after unplugging it and plugging it back in; the fans lit up for half a second and then again nothing.

I am assuming it's the PSU. I just replaced it (about two months ago) with a relatively cheap EVGA model from Best Buy, lesson learned. My plan is to upgrade to something much more reliable. I just want to make sure my assumption of the PSU being bad it correct.

The PSU is currently out of my computer but when everything was plugged in the motherboard lights were still lighting up. This is the main reason for posting. Can that happen? Can a PSU be bad and the motherboard still be lighting up? Sorry if that's a dumb question haha.

Any help is really appreciated!

Here is the cheap PSU I replaced my old one with recently: https://www.bestbuy.com/site/evga-80-plus-600w-atx-12v-eps-12v-power-supply-black/8511029.p?skuId=8511029&ref=199&loc=kXQk6*ivFEQ&acampID=1&siteID=kXQk6.ivFEQ-tFgVAk3aacNRnP44x8KqlQ

My mobo is an ASUS M5A97 LE 2.0
 
Solution
Most modern power supplies are able to output -12, +12, +3.3 and +5 volts

https://en.wikipedia.org/wiki/Power_supply_unit_(computer)#ATX12V_standard

If the power supply was unable to give 3.3 volts or 5 volts, but the 12 volts still worked you could get fans and lights, but nothing else.

90% of the power supplies that I see fail stop working altogether instead of just parts of it, but it is possible.

EVGA is a good brand, but you bought pretty much the lowest/cheapest model of that brand.

The "80 Plus" stamp was a dead give away and basically means they created a power supply by cutting as many corners as possible.

The 80 Plus certification is how the efficiency of a power supply is rated.
https://en.wikipedia.org/wiki/80_Plus

An...
Most modern power supplies are able to output -12, +12, +3.3 and +5 volts

https://en.wikipedia.org/wiki/Power_supply_unit_(computer)#ATX12V_standard

If the power supply was unable to give 3.3 volts or 5 volts, but the 12 volts still worked you could get fans and lights, but nothing else.

90% of the power supplies that I see fail stop working altogether instead of just parts of it, but it is possible.

EVGA is a good brand, but you bought pretty much the lowest/cheapest model of that brand.

The "80 Plus" stamp was a dead give away and basically means they created a power supply by cutting as many corners as possible.

The 80 Plus certification is how the efficiency of a power supply is rated.
https://en.wikipedia.org/wiki/80_Plus

An 80 Plus with no metal attached to it can have as low as an 80% efficiency rating at 115 volts.
The extra 20% is turned into heat, which all electronics don't like.

The 80 Plus Gold has an efficiency of 90% at 50% load meaning much less heat is generated and therefore the power supply should last longer.

I tend to stick with "80 Plus Gold" or higher efficiency power supplies like;

https://www.newegg.com/Product/Product.aspx?Item=N82E16817139210
https://www.newegg.com/Product/Product.aspx?Item=N82E16817438017


Do note the warranties on the 2 power supplies above; 7 years for the corsair and 12 years for the EVGA.

The one you purchased from best buy had a 3 year warranty.

 
Solution
Aside from actual power supply failure a working power supply will shut off if the switching regulator sees an unstable voltage. You might consider detaching all the USB/firewire devices you can, shut all power down, hold the power button for a few seconds to reset, put the main power back on, and then try to boot without anything USB/firewire. The reason I mention USB and firewire is due to the ability to consume power...perhaps it is a power failure, but maybe it is something consuming power and not the actual power supply.
 

bignastyid

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Moderator
MERGED QUESTION
Question from kevinstyles : "Computer died this morning, need help determining which part to replace."



 

bignastyid

Titan
Moderator
MERGED QUESTION
Question from kevinstyles : "Dead PSU or dead Motherboard?"