If it's only working with the Dell "ATX" PSU, you likely need to use that, or you can use this: http://www.ebay.com/itm/Athena-CABLE-DELL-X-A … -AAAOxyOlhS5ZQL

You will need to re-pin a regular power supply. Dell was stupid like that, and had to go proprietary.

Don't quote me on this, but you may be able to just take the pins out the back of an ATX connector with a pair of pliers and throw them back into the right position.

However, re-insertion may not be possible, and you could end up breaking stuff.

The other option is to chop off the connector with maybe a few inches of wire back on the ATX connector, and re-solder all the connections to the right location.

Do this only if you are confident in your ability to solder wires, and do NOT do it without heatshrink tubing or liquid electric tape (Regular electrical tape is NOT good enough, do NOT even try it)

The pinout is the only thing different AFAIK.

The other solution is to just use a Dell PSU. I do have one spare that I am not using, but VOGONS isn't a place to sell it, and you could probably get a better deal elsewhere. TBH, if you live in a place like I do, go for a few walks around where you live over a few weeks and look to see if someone has tossed out a Dell machine, and grab it.

Be warned that PSUs from Dell are probably the worst you can get. They are not built to last, they are built to be cheap to buy, and cheap to replace.

I don't suppose anybody knows what the correct pinout would be for a 486 era DELL?

I've got a spare 24 to 20 pin ATX adapter that I can chop up and modify, so I don't have to actually destroy a working PSU to try and get this working.

The pinout of the PII-era DELL PSU that I have isn't the same, as although it will occasionally allow me to power the board on via the power button, it won't POST or do pretty much anything else. Now this could be due to the motherboard being faulty, but I have no way of telling at present.