Motherboard on-off loop -- help? :o

[RAZ13L]

Firstly, hi, new here and while i wouldn't want to introduce myself with a question i need a bit of help so please forgive me on that.
First and foremost the specs:
i3-540
H55M-UD2H
2x2GB Corsair Dominators 1333
GTX 470
Thermaltake TP XT 775W
some WD HDDs
--------------------------------------

Now, today i was replacing the stock heatsink for the H50 i got through a trade because my previous (Cogage Arrow) doesn't fit on this motherboard if facing one direction (brackets and capacitators near CPU socket clash) and doesn't fit the other way because of my Dominators. So back to today, i took off the stock cooler, put on the H50 and when i proceeded to hit power, it would turn on with all the fans/LEDs going active and then shut off again after about 2 seconds, and it just repeats. Everything was working fine prior to taking off the stock heatsink and i'm very sure i didn't damage the CPU/MB or anything (no carpet or anything in my house so no static either but i touched metal first :p). I put back on the stock cooler and got the same, and tried another PSU, and i took out the video card and tried single sticks of my dominators and still get the same so it's probably the motherboard but i'm not sure since i've never had this. Can anybody help? Thanks, much appreciated.

Nevermind, faulty PSU i had a feeling.

[Dark Mantis]

Yes often it is down to the PSU in those circumstances. Anyway as long as you have managed to find the problem.

[RAZ13L]

Ok i just did more troubleshooting and it's not the PSU. I took out my old backup system and tried my PSU in that with the 470 so there is a bit of load on it and ran furmark and prime simultaneously for an hour and it was all fine and i'm still getting the issue :\ Since i don't have my AMD system anymore, i can't test if it's the ram either but reading around i've seen other people experiance this too but their casues have been different each time. Any suggestions? Thanks folks

[Dark Mantis]

The motherboard LEDs all lighting and fans going then shut off before resarting is normal if you have disconnected the mains supply. But after that initial on/off/on again relay it should just carry on booting into the OS.

The only thing I can think of if you are 100% sure that it is not the PSU is to try clearing the CMOS and loading the Optimised BIOS Default settings and see if that helps.

[RAZ13L]

The thing is i can't get into the BIOS at all. I hit power, and everything turns on for about 2 seconds, and then turns off for about 4-5 seconds and repeats. I've tried to clear CMOS however by shorting the jumper but that didn't help and even took out the battery.

[Dark Mantis]

Did you remove all the power first when clearing the CMOS and you need to leave the battery out for at least ten minutes.

[RAZ13L]

Yes i did, i disconnected everything, and i took out the battery for about an hour.

[Dark Mantis]

In that case I think that it is quite possible that you might have damaged the CPU socket when you removed the old heatsink and reinstalled the new one. You will need to remove the CPU and look carefully at the pins in the socket to see if any are out of alignment or bent. If you would like to post a couple of Macro photos here we can check them for you.

[RAZ13L]

Hi

Thanks for the suggestion but i've already inspected the pins and the cpu (contact pads) and there is no damaged, bent or burnt pins and the cpu is in the condition it was when new (these things are only about 2 weeks old).

[RAZ13L]

Ok just to update a mate brought over his pair of ram and i tried it and i still get the same issue so it's either the mobo or cpu. I'll RMA both to the store i got them from and whichever has the problem can be fixed.

[Dark Mantis]

Yes probably the best way. It always helps when you have purchased both items from the same retailer.

[Fatman]

Before you RMA try taking the board out of the case and see if it will boot. Put it on a phone book or something, just to rule out a possible short after you changed the heatsink...Test your ram on your mates mobo if need be, no point sending in perfectly good ram or mobo for that point.

[RAZ13L]

Tested ram, its fine and took it out of the case way befoer. It's either the mobo or CPU so i'll send both. Sending on monday