Gigabyte GA-P67A-UD3-B3: won't power up

[robig2]

Hi,

I`ve just bought the GA-P67A-UD3-B3 with a core i5 2500k. Plugged everything in to find that it won't power up at all (not even fans).
After trying several things I narrowed the problem down to the PSU. Plugged in a thermaltek lightpower 450w PSU and mobo started when plugging my enermax liberty 620w it won't -> sound like the problem... however when i connect the 620w to my older comp (DFI bloodiron p45 with c2d e6400 @ 3.5ghz) it work perfectly!

I`ve looked at specifications for both the psu and the board and couldn't find a single thing that would indicate they are not compatible. Can anyone help me with this please?

 

[rolli59]

Start by running through this guide step by step http://www.tomshardware.co.uk/forum/261145-13-perform-steps-posting-boot-video-problems
Strange with the PSU!

 

[robig2]

Went through it before I posted.

I just don't see whats the difference between them... why doesn't the new mobo like my psu?

here is the psu specification for reference:
http://www.bjorn3d.com/articles/Enermax_Liberty_ELT620AWT_620W_Power_Supply_Review/863.html

 

[robig2]

I think I found the problem: I`ve tested each pin on both power supplies and found that my 620w give 2.97v on the 3.3v rail whil the 450w give 3.4v

The voltage should be at +/- 5% and mine is exactly 10%.
I guess I`ll have to get a new one and let it work with my old rig as long as it can.
Thanks for trying to help