Phase LED's fluctuating, no post.

Hi there, as briefly described in this thread I've got a problem with a bundle I bought.

- CPU: Intel Core i5 2500K 3.30GHz @ 4.40GHz Sandybridge CPU
- Motherboard: Gigabyte P67A-UD4 (Socket 1155) DDR3 Motherboard **B3 REVISION**
- RAM: Corsair XMS3 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel
- Cooler: Corsair A50 CPU Cooler

The problem is it won't post, what seems to happen is that the phase LED's on the board all light up and on close inspection don't look very stable, they seem to be fluctuating. The fans all spin up but HDDs dont. There are no beeps at all.

Anyone know what's going on here? I tried it with absolutely nothing connected but the PSU and it still occurs. I'm confident my risers are in the right places and there are no spare ones sitting between the mobo/case.

My points of uncertainty are the A50 cooler, and my PSU's 12v connectors.
The A50 has a bracket behind the CPU and even though it's held off by plastic washers and a piece of plastic the same shape as the bracket, it still is really close to the metal behind the cpu socket... could this cause a problem?
The PSU has 2 seperate 4pin 12v connectors for the CPU, one has pins alternating between square and curved, the other is all curved so could fit in either slot I guess, are these exactly the same? is there an order in which they should be plugged in? Can I plug in the second one (all curved) to my old mobo which only takes one 12v connector, just to test that it works?

Spent all evening on this, removed and reseated the heatsink three times (havent touched the CPU because I worry about my warranty...) but I'm at a total loss

Any help is greatly appreciated.

If by the LEDs fluctuating, you mean flickering, then I'd definitely try it with another PSU. Sounds very dodgy.

Edit:

This is the connector you should be using. It should only fit naturally without any fighting into the correct socket. Very likely there will be an 8 pin like this:

You should be able to see which side it fits into naturally from the plug. (In the picture one side is capped to show you).

My PSU has two of those 12v's and the clips on them sit next to each other when both are plugged into the board, should I only be using one? Is that cap there because I shouldnt be filling it?

My old mobo has only a 4 pin socket rather than 8, so I've never used the 2nd 12v connector and have no easy means of ensuring it works.

If you have 8 pin, use 8. The cap is there in case you only have a 4 pin plug. Either would be fine.
You can only use one half of the 4 pin in either half, they are keyed to prevent it. They are probably fed from the same lines anyway.

I would build pc outside of case just in case!

So is it safe/possible to put just the one 12v connector in to test if the second one is what's causing the grief?

Would a motherboard short cause this symptom? The power doesn't turn off it just seems to fluctuate.

It does sound like a PSU issue. However since you bought a bundle quite recently my advice would be to contact OCUK sooner rather than later and explain your problem. They are very good at sorting these kinds of things out immediately. Might just need a PSU swap out.

One quick question - is the bundle an over-clocked bundle?

Yes it is an overclocked bundle.

Well for anyone interested or who might experience the same thing, the PSU appears to be at fault. I'm surprised since I have a near identical PSU running an i5 setup on another machine (work PC's), but that PSU runs this board fine *shrug*.

Nice new corsair jobbie ordered, and my mind is somewhat at rest knowing the problem!

Thanks for the help guys, even though this was a rather vague/weird issue!