psu Trouble shooting DOA psu

[Aidans]

Hello . Today I received my new gigabyte p750gm as an upgrade for my old evga b3 but it appears to be completely dead on arrival. I have tested it with 3 different outlets and 2 different cables but I cannot get it to power on. When it is plugged in to the wall and I have everything plugged into the psu the motherboard rgb light will turn on but nothing else appears to have power. Please let me know if you have any questions because I have no idea where to go from here 

[eeeee1]

run some psu tests. here is one from antec:

http://support.antec.com/support/solutions/articles/1000015319-is-my-power-supply-dead-the-paperclip-test

since your mobo lights up, i am somewhat tempted to say that some of your cables may be defunct. try different power cables for your internal sata, pcie, cpu and such