What's the pinout for a PSU with BOTH 24 and 20 pin connectors?

  Riyock 19:56 19 May 2013

Hi all,

This is my first post so please forgive if I'm posting in wrong place, etc.

I am trying to figure out the pin-out of my PSU as I want to test to see if it is working properly. Am confused by the connectors it has.

I have a Dell Precision T5400, which has an EATX format mobo. On this mobo there are two PSU connections: P1 which is 24 pins and P2 which is 20 pins.

The PSU I have is an 875W unit which has the 2 connectors mentioned plus 1x 4-pin mole and 2x 6-pin connectors:


My PC won't boot, but there appears to be some power to the mobo, so I think that either it's the PSU or the mobo which is faulty. If I know the correct pinout i should be able to test with a multimeter?

Unfortunately I can't find anywhere on the internet information about my type of PSU, it seems most ATX types have either a 20 or 24 pin connector not BOTH OR at least those are the only articles that pop up during a Google search.

Would really appreciate any help on this. Thanks in advance!

  bumpkin 20:47 19 May 2013

Just enter "ATX pinout" into your search bar and you should find something that will give you the colour codes and voltages then you can test it with your meter.

  T0SH 21:02 19 May 2013

If you go here you can download the manual for this machine


download the user manual and look in the adding and replacing parts section for power supply dc pin assignments

Cheers HC

  Riyock 23:16 19 May 2013

Thanks TOSH, that is exactly what I wanted!

Also after testing with my meter I realised that the colour coding is the same as what is used for a standard PSU - so that helps too.


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