Corsair HX520W PSU causing new setup to not post. Old build still posts with PSU

[Aharami]

OK so here's the dilemma I'm facing and I cant figure out why one PSU is working and the other isnt.

I just put together a new build
GA-Z68X-UD3H-B3
i5 2500k
Thermalright Ultra 120X w/ 1156 bolt thru kit
GSkill ripjaws DDR3

My old build is a Q6600, ABIT IP35-E, 4 gigs od DDR2800 RAM, 560ti. Even had the old build OCed to 3.2 GHz

My PSU is a Corsair HX520W that has been running rock solid for years and never gave me any problems with my old build.

Put together the new build, hooked everything up to my Corsair PSU, and it wouldn't post. Even created a thread about it in MB. When I hit the power button, mb LED flashed quickly, all fans turned on briefly, and then everything turned off. Nothing else happened. Even if I hit the power button again, nothing. I had to toggle the PSU's power switch to recreate the scenario.

Thought I had the power switch leads connected backwards...took it out and flipped it. Same thing.
Took out RAM - same thing
Unplugged everything else - same thing
Unplugged all other rails from the PSU except the ATX 24 pin and 8 pin. Then the LEDs stayed on (but flickered slightly), fans stayed on. But no beep, and no post.

So I tried using the OCZ Fatal1ty 550W I had in my HTPC. Surprisingly, new build booted up and posted with this PSU. So I was thinking the Corsair PSU went bad. But here is the kicker - Tried old build with the Corsair, and it powered up, posted, and went into windows.

So I tried new build again with Corsair - no go. Still the same result. Switch Corsair back to old build and power new build with OCZ - both works.

I cant figure out why my new build works with the OCZ PSU but not the Corsair PSU...when the Corsair is proven to be working.

Any thoughts?
:\

 

[Meghan54]

Have seen this mentioned a lot before. Bet it's the "signal good" the motherboard feeds back to the power supply....too short a signal for that Corsair. Not a widespread issue, but have seen this complaint before more than once with some Corsair ps's and current Intel motherboards.

It's usually suggested to RMA the power supply.

 

[Aharami]

i guess this is a known issue. I called up Corsair and as soon as I explained the problem to them, they sent me a RMA form. Didnt even ask me any questions. Thats a very plausible explanation you provided, Meghan. I wish the Corsair tech would've confirmed it. I'll post in the corsair forums to see if I can get an explanation over there confirming what you said

 

[Meghan54]

I actually found out about this particular problem via Jonnyguru's forums.....

http://www.jonnyguru.com/forums/