PSU woes...

OK, some background. For the last 6 months I have been running an Athlon64 3000+, 512MB 7900GT, 1GB RAM, 2 HDDs etc. from a crappy 350W PSU that came free with a £25 case 4 years ago.

No problems with stability, but recently the noise of my PC has been starting to bug me, so I bought a new PSU, heatsink/fan and case. The new power supply is a Seasonic S12-430.

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. :angry:

I'm pretty pissed off right now so I'm going to bed, but I thought I'd post here and check any replies in the morning. Any ideas? Dead PSU?

Sorry for the long post.

What motherboard? I've seen exactly this problem myself with Biostar motherboards.

The problem may be that the motherboard requires -5V, but most of the latest PSU's (Seasonic included) don't supply it. Tagan PSUs are a good alternative, and they have the -5V supply.

I believe the motherboard is a Foxconn NF4K8AC-RS-1.0 (NForce4, Skt 939).

Having trouble finding it on the Foxconn site, but there's a detailed review here.

is this the beast http://www.foxconnchannel.com/Produc...D=en-us0000020

I don't think the -5v issue seems to be the problem as it is not mentioned in the power supply section of the manual.....I stand to be corrected of course...

Here is your board at the Foxconn site: http://www.foxconnchannel.com/en-us/...D=en-gb0000131

Here is a link to its users manual: http://www.foxconnchannel.com/en-us/...NF4K8AC-RS-1.0 Page 14 refers to power supply.

Here is a link to the datasheet for your Seasonic S12-430: http://www.seasonic.com/pdf/datasheet/01PC/S12.pdf

The motherboard doesn't appear to require the -5v as lynx mentioned.

But the motherboard manual does mention something about:
ATX 12v Power connector: PWR2 and AUX PEX PWR connector: J2A1

Do you have those connected?

Accat13 appears to be right, it looks like that board doesn't require -5V. The manual shows the connector (pin 18 on a 20-pin connector, pin 20 on a 24-pin connector) as NC. If you wanted you could verify that by removing the wire from the plug on your old PSU (it's the white wire) and trying that again.

I take it that you've tried the PSU in another machine. If not, now would be a good time to do so. Just put the machines back to back and swap the power connector from one mobo to the other. Unclip the extra 4 pins if necessary.

Thanks so much for the replies and links guys, it's really appreciated. I've not tried the PSU with another machine - I've not really got one handy but I'll see what I can do over the weekend.

Quote:

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Originally Posted by Virtualbody1234

But the motherboard manual does mention something about:
ATX 12v Power connector: PWR2 and AUX PEX PWR connector: J2A1

Do you have those connected?

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That J2A1 connector I do not have connected. To be honest I'm not sure what it is. I wish the manual showed me more where it is actually located - unfortunately I'm at work so not with the PC at the moment.

However I can't think of any obvious connectors on the motherboard that I had missed, nor any cables on the PSU that might connect to it. I should note that when using my old PSU that works, I had everything plugged in the same places as with this Seasonic.

The J2A1 connector is a standard molex connector on the bottom right of the board. I did have it connected - unfortunately it is not the cause of my problems.

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?

Quote:

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Originally Posted by Skillian

The J2A1 connector is a standard molex connector on the bottom right of the board. I did have it connected - unfortunately it is not the cause of my problems.

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?

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I agree but i'd still want to try it in another computer to make sure...
If it's not a psu problem and you get the same one again that would be kinda annoying.:pinch:

Yeah, that's my worry.

I'm gonna set up my old AthlonXP system on tomorrow or Saturday and see if it works in that.

Just thought I'd let anyone know if they were interested - finally got the guts to RMA it and it was indeed faulty.

Should receive a replacement soon.