Does GA-X58A-UD3R require -5v terminal at 24 pin ATX connector?

[natman]

As the title asks....

My brand new corsair TX950 has no -5v wirel at the ATX connector, but the motherboard manual shows it being present in their ATX connector diagram. 
 
I have checked the operation of the psu via the method outlined at their website, (jumping green to black etc.) and it checks out fine with all voltages correct  and at the correct terminal positions.

The PSU will run as many loads(fans etc)  as i can find to put on it, but if the motherboard is plugged in it cuts out after just a second.
(this was tested with the MB resting on a piece of cardboard with just the cpu and fan, on/off switch and case speaker fitted.
No post beeps, just everthing shutting down after a second bar the green and amber phase leds next to the ram.

I put this down to a faulty MB and returned it to the retailer, but they have called and stated that when they tested the MB it works fine.....
Now i'm at wit's end trying to work out why my PSU and MB will not work together.

[onemilimeter]

ATX-2 does not have "-5V"...

http://pinouts.ru/Power/atx_v2_pinout.shtml

I'm using UD3R too and OCZ600SXS which does not have "-5V" supply...

[Dark Mantis]

Hi and welcome to the Gigabyte Forum.

The -5v line is something left over from older hardware that is not used today hardly at all. That is why your new Corsair PSU doesn't even include it.

The first thing I would look at is make sure the 12v EATX connector near the CPU is plugged in properly. Failing that I would check the CPU socket and make sure that there are no bent pins present. If you want to take some macro(close up) photos and post them here for us to check that is fine.

When you tested it you say it was on cardboard and there was no chance of a short circuit on the back?

[natman]

Yes it was sitting flat on a cardboard box.

I can't post any  pics yet as the MB is still in the post coming back to me from retailer(down side of internet retailers i guess)
I did have the cpu off twice to check for bent pins with a magnifying glass and could not find any.  The retailer could not find any either, and claims the MB boots and emits correct beeps.  

I have checked the continuity of the on/of switch thinking it maybe was'nt staying on but it tests ok.
My case speaker has 15.5 Ohms of resistance so i don't think the MB is seeing a short there....

The retailer has offered to do further diagnosis if i send my PSU, Graphics Card and memory back to them, being fully aware the cost of doing so would probably equal the cost of another motherboard     (they are on the otherside of the country)-Australia

[Dark Mantis]

OK, I understand the situation. Do you still have your CPU? If so you can look at the lands underneath and see if there are pin marks on them. If it has been refitted a couple of times there will be more than one mark on each land but  they should all have marks and be fairly central.

By the way the power button is only a momentry switch and doesn't need to latch on just make the connection and then release.