New psu not powering pc

[idkfa]

Hi all,

I just swapped out an aging psu for a Corsair HX1200i. The problem is when powering on all the fans come on and the light on the cpu cooler flashes but there is no boot or post. System worked fine before the swap. There does not appear to be a short, have I got a bad psu? Any suggestions for what to try? Many thanks in advance.

 

[idkfa]

Thanks for the reply. I have checked the cables and all looks good and gfx has 1 cable per power pin. I have just put the old PSU back in and everything is working. I read online that the CPU power can be in any of the ports labelled 6+2 PCIe and 4+4 CPU, is this true?

 

[idkfa]

That could be it. The old one is an Enermax and I left one of the sata power chains connected. It only had a HDD and DVD drive attached do you think that's it?

 

[idkfa]

I'd say it's a fair chance.

Totally unplug the SATA cables at the PSU end to test. It should hopefully post and show a no boot-drive error.

The connected drive was just a data drive not my OS, it seems fine as is the DVD drive which is good. Will swap out the PSU again and try without using any of the old PSU cables, thanks all and yes I am a huge Doom Fan

 

[idkfa]

Hmm swapped out the old cable and the cpu cooler and all case fans and lights come on now but its restarting every 5 seconds without even posting. I have removed all braided cables and only used the corsair provided cables. Bios reset but it's doing the same thing. Any ideas?

 

[idkfa]

It's working fine with the old psu. I tried removing the GPU to rule out power to that but it's still on the 5 second cycle. It really seems like it's the 24 pin atx or the cpu power but I don't know what's wrong.

The motherboard is not powering on so no diag lights on it.

 

[idkfa]

I think you are right its either a cable or the PSU. It comes with 2 CPU cables and I tried both. Swapped back to the old PSU again and all is okay. Is it worth raising with Corsair or just RMA?