Seasonic PSU woes...

[Skillian]

Hi all, sorry to make my first post here a "Help me!" thread.

For the last few months I have been using a no-name 350W PSU to power an Athlon64 3000+, 512MB 7900GT, 1GB RAM, 2 HDDs etc. Stability has been fine but the noise was starting to bug me, so I bought a new PSU, case and heatsink/fan. The new power supply is a Seasonic S12-430. My current motherboard is a Foxconn NF4K8AC (NForce4, Skt 939).

I hooked everything up (built about 5 PCs now so getting quicker) and when I push the power button, the fans spin up for a second or two and that is it - nothing on the monitor.

After messing around pulling out components etc, I tried with my old PSU and instant success. This is a PSU with a 20-pin power cable and a 24-pin motherboard but still it works better than my new Seasonic.

Any suggestions? Dead PSU? Someone suggested I might need a -5V line that my PSU doesn't have, but I can't find much about that on my Google adventures.

Sorry for such a long post

[Tak]

Have a look here and here.

[Koolpc]

Did you plug in the 4 pin PSU connector on the mobo?

[Skillian]

Have a look here.

Thanks, that sounds very similar to the problem I'm experiencing. However, they seem to say that the new sleeved Seasonic S12-430 has fixed the problem - I have the new sleeved version (with 4 S-ATA connectors) but it certainly doesn't seem to be fixed for me.

Regarding the 4-pin connector, I do have it plugged in, although it's interesting to note that when using my old crappy PSU, the computer will boot whether that 4-pin is plugged in or not.

[Skillian]

I've just tried shorting the 4th and 5th pins, and I get the same response - the fan spins for a second, then stops. This would seem to indicate to me this is a broken PSU.

Do you agree?

[Skillian]

Just in case anyone was interested or somehow put off the S12-430 - I finally got the guts to RMA it and scan.co.uk tell me it was indeed faulty. I should receive a replacement soon.

If anyone from Scan is reading, thanks for the quick RMA process and for keeping me informed - it was only collected yesterday and today it has been tested and I've been informed of the results.

[shaithis]

Regarding the 4-pin connector, I do have it plugged in, although it's interesting to note that when using my old crappy PSU, the computer will boot whether that 4-pin is plugged in or not.

With or without the 4 pin connector, the PC sould work.

When the CPU is being stressed, that power line can make the difference between stability and instability though

[notsobig]

Have a look here and here.

Thanks for these links Tak. Wow, I didn't know that, maybe this could be related to the problem I'm currently having. Cheers.

P.S. Glad to know you've solved your problem Skillian.