Fail first startup. Motherboard's LED doesn't even come on

[Arkanus]

Hello.

I just built my new rig and then proceeded to turn it on for the first time. After plugging the PSU power cord into the wall socket, I noticed that the motherboard's LED doesn't even come on.

And of course, the computer doesn't start when I press the "on" button

The PSU is a Corsair AX850, motherboard is an Asus Sabertooth 990FX. The whole computer (including the PSU and the mobo) is made with new parts.

Since the motherboard's LED is off... I'm assuming that it might be a faulty PSU? It seems that a lot of people had problems with faulty AX850's. That's one of the reasons why I'm starting to think that my PSU might be DOA: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139015&Tpk=ax850


Any idea about what might be wrong with my PC?
Thanks a lot in advance!

 

[cmichael138]

Here's a basic check if you don't have a spare PSU to substitute or a multimeter:

http://www.metacafe.com/watch/729606/how_to_test_your_computers_power_supply_psu/

 

[JKatwyopc]

I hope this doesn't sound lame but this happens to me almost every time I work on my computer. I forget to turn "On" the little switch on the back of the PSU. Never Gets Old! Never Fails to Scare the ()$@)$ out of me! Never fails to give me a good chuckle at myself when I realize I just did it yet again for the umpteenth time! And I NEVER seem to learn my lesson! Did you check that little power switch to make sure you turned it to "ON". Yeah, the one labeled "0|1".

 

[Arkanus]

I hope this doesn't sound lame but this happens to me almost every time I work on my computer. I forget to turn "On" the little switch on the back of the PSU. Never Gets Old! Never Fails to Scare the ()$@)$ out of me! Never fails to give me a good chuckle at myself when I realize I just did it yet again for the umpteenth time! And I NEVER seem to learn my lesson! Did you check that little power switch to make sure you turned it to "ON". Yeah, the one labeled "0|1".

Haha yeah I know the feeling , sadly it didn't happen this time. The motherboard's LED is always off, doesn't matter if the PSU switch is ON or OFF.

 

[JKatwyopc]

Hmm, have you tried going through this troubleshooting guide: http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems

It can find almost any problem that you can have with a new or rebuilt system.

Try disconnecting the PSU from everything and then, on the 24 pin mainboard connector, short the green wire to any black wire with a paperclip. If PSU will NOT power on then its the PSU.

 

[Arkanus]

Ok, I just did the green-black wire thing and the AX850 PSU didn't show signs of "life" at all, even attaching a blue leds fan with a 4-pin molex connector.

I connected an old Hiper Type-R 580 W to the motherboard, plugged the power cord into the wall socket without turning the computer on and voilà... the motherboard's LED comes on for the first time (the mobo made a weird "click" noise though).

I repeated the process two times to make sure that it was working fine and yes, the LED kept coming on with the old Hiper PSU (this time without that "click" noise).

This means that I got a DOA AX850. Hard to believe that this kind of stuff can happen with a $180 Corsair powersupply

 

[cmichael138]

Pretty rare for a reputable company like Corsair, but "stuff" happens with the best of them. It's a bummer but glad you found the culprit quickly. Good luck!