Modding a 20 pin PSU for 24 pin mobo? Dangerous?

Daravon · Post by **Daravon** » Thu Mar 25, 2010 6:08 pm

I have a DFI RS482 mobo, fanless 8400 videocard, 90w AMD 3700 with giant Zalman, and no power supply. Actually I have a 250W PSU from an old dell, but it does not have the right plugs. The main plug is only 20 instead of 24 pins (I think). So the mobo will not even post.

I looked up the plug wiring diagram and it seems like the 4 extra plugs are voltages that could be got by splicing the current lines and branching them to the leftover pins. However, I'm sure those extra, redundant pins were added for a reason, and I don't want to even risk starting a fire or anything.

I'm not sure what PSU to get otherwise. I have a SeaSonic SS-300SFD in my other system and I've been impressed so I think I will get another one of those unless there is a similar-priced, quite, quality PSU I should get instead.

MtnHermit · Post by **MtnHermit** » Thu Mar 25, 2010 6:57 pm

Daravon wrote:The main plug is only 20 instead of 24 pins (I think). So the mobo will not even post.

Not posting is almost always because you don't have the 4-pin CPU power plug connected. 20/24 pins is relatively unimportant. If your existing PSU does not have a 4-pin CPU connector then it's incredibly old and should be tossed.

What ever PSU you get, be sure it is 80+ rated, worth the extra $$$.

ces · Post by **ces** » Thu Mar 25, 2010 8:38 pm

You can buy adapters for this. Go to performance-pcs.com

Vicotnik · Post by **Vicotnik** » Fri Mar 26, 2010 1:01 am

Be aware that older Dell PSUs don't follow the ATX standard. It's possible to damage the motherboard or the PSU or both if such a PSU is used in a normal motherboard. Don't know exactly when Dell finally got their act together.

It's possible to build a converter though. Dell scrambled the wires and it's possible to undo the mess with a modified ATX extension cable.