Hey all I am using an old Dell Precision R5400 which has the 750w hot swap-able power supply. Problem being, since its a dell, the ATX pin layout is different than that of a normal, standard ATX 2.0 power supply pin out.

What I found to be the Standard ATX 2.0 pinout: enter image description here

I have taken a volt meter to the R5400's ATX pinout and this is what I come up with:

 [1] Ground     [13] Ground
 [2] +5v        [14] +5v
 [3] +5v        [15] +5v
 [4] +12v       [16] +3.3vsb
 [5] -12v       [17] Ground
 [6] Ground     [18] Ground
 [7] +3.3vsb    [19] +12v
 [8] +3.3v      [20] +3.3vsb
 [9] Ground     [21] +12v
[10] +3.3v      [22] +3.3v
[11] +3.3v      [23] +3.3v
[12] +3.3v      [24] +3.3vsb

Thankfully my motherboard's manual shows the pinout of it's ATX power supply connector: enter image description here

So some questions are still wondering inside my head:

1) What voltage should the PSON# be?
2) What voltage should the Power OK be?
3) As you see, I do not have access to a +5Vsb from the R5400 PSU.
   Can I just use a normal 5vdc for that (or somehow get 3.3vsb 
   that I do have to work with it)?

Currently this is my pin-out for my new connector from the R5400 connector to the motherboard: enter image description here

So do you see anything wrong with the above? Just making sure as I do not want to fry a $500+ server motherboard over one wrong pin.

  • Your big problem will be the 5VSB. This needs to be supplied to the mobo before it can assert PSON# so you can't use a normal 5V line and 3.3V won't be enough. You may be able to feed the 3.3VSB into a boost regulator to get 5V but I don't know if the line will supply enough current.
    – DoxyLover
    Commented Apr 24, 2015 at 6:33

1 Answer 1


PSON is short for Power Supply On, so that is the same as PS-On from the ATX spec, and you can just power the power good with the 5v signal.

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