I recently purchased that same power supply and it turned out the AC power cable was bad. After trying all the hard stuff first I replaced it with a old cord I had and the thing powered right up. It took Corsair a month to send me a replacement, their customer service is "lacking" from previous days.
I tried that last night at 1:00 Am . I snagged the one right off my old system and nothing. Power flowing through the unit & it's cables, I'm suspecting the problem from that point.