Help needed with custom PSU.

[TheDogFather]

I really could use some help on this.

I've got a PSU that has various outputs but no 3.3v line, to get around this I've got a integrated switching regulater to drop a feed off the 5v down to 3.3v.

Theres several outputs on the PSU +12v -5v -12v +12v each with a 0v next to them. I've checked with a multimeter and it doesnt matter which 0v is used with which output.

But the +5v is seperate also with its own 0v.

If I measure the 5v and one of the other 0v's, I get strange readings.

So my problem is, when I connect the wiring harness up, I need to figure out which com wire goes to either the 0v next to the 5v or one of the others.

I'm hoping the drive connectors will be easy enough, the com wire next to the 5v being its partner and the same with the 12v.

That really just leaves the ATX connector.

This is hard to explain, so its most likely hard to follow, but I could really use some help, I started on this about 8 months ago.

TDF.

[TheDogFather]

I'm a begginer with electrics so any input would be apreciated, apart from suggestions to buy a supply, give up, or use it to power a pelt. ;)

To simplify things, look at it like this. I have a supply with a 12v and com output, and also a 5v and com output.

As expected I get 12v from one and 5v from the other, unless I mix the com outputs up, then I get either 20v or -1.5v depending on order.

Can anyone explain why this happens ?

Are all the com wires in the boards atx socket connected to each other ?

TDF.

[Vlad Draculea]

to probable wont be able to read if it ndaded your eyes