Question Pin diagram of P2 connector for HP Elitedesk 800 G1 Tower


Dec 9, 2018
The information I am about to write below is all I could find. Information can be WRONG so please feel free to correct this information in comments. Thanks.

I am upgrading my old PSU in HP elitedesk 800 G1 tower with third party PSU. I want to know about P2 connector. P2 is the white connector shown in the attached image below.

There are 4 wires coming from power supply to P2 connector. P2 connector has 6 holes. and 2 of those are left empty while 4 holes have wires in them which are of different colors. I want to know what each wire in that P2 connector represents so I can make a P2 connector for on my own for my HP elitedesk 800 G1 tower. Old PSU that came with HP elitedesk 800 g1 tower has the following color scheme:

Color scheme of custom HP PSU for HP 800 G1 tower:
Please see the image attached below to compare with what I am about to write

  1. Pin 1 and Pin 2 are empty meaning no wire is inserted in Pin 1 and Pin 2.
  2. Pin 3 has grey wire in it.
    • I am assuming that grey wire means PWR_OK (Power ok or Power Good (PG)). On 24 pin connector, PS_ON is on pin # 08
    • PG is written besides this grey wire on the PSU of HP elitedesk 800 G1. I am assuming that this PG means Power Good.
  3. Pin 4 has green wire in it.
    • I am assuming that green wire means PS_ON (power supply on). On 24 pin connector, PS_ON is on pin # 16
    • REM is written besides this green wire on the PSU of HP elitedesk 800 G1.
  4. Pin 5 has white wire in it.
    • No idea what white wire does. I opened the PSU that came with HP elitedesk 800 G1 tower and TAC is written with white wire.
  5. Pin 6 has half red and half white wire in it.
    • Again no idea what this wire does. FANCMD is written on the PSU that I opened.

I noticed that if you buy a "30CM Modular Power Supply Cable ATX 24Pin 24 Pin Female to 6Pin 6-Pin Male Mini 6Pin Connector for HP Elite 8100 8200 8300 800G1" from, then P2 connector will have strange wiring scheme. Pin 1 and Pin 6 are empty in the link of aliexpress. but they are saying its for 800g1 as well. this is what confusing me. That original PSU that came with HP elitedesk 800 G1 tower has Pin 1 and pin 2 empty while the link above shows pin 1 and pin 6 empty yet they are saying that it will work for 800 g1 tower. what is this? am I missing something?

So from all the above information, I wanted to ask you guys that am I correct about pin 3 and pin 4? is pin 3 really PS_ON and pin 4 is PWR_OK? and should I just ground Pin 5 and 6?

I am asking this because I don't want to fry my motherboard because of wrong connections.

Thanks in advance for the comment that you will write.


Aug 27, 2015
So the power adapter won't work...
This adapter is not designed for 800G1 so it won't work in its original state (i.e. the claim that it works for 800G1 is incorrect). Since it already has the correct plugs 6-pin black and 6-pin white, it should be easily modified. You need to read and understand what 'slickpuss' said in another thread that I refer to (see link from my post above). Assuming all wires in the 6-pin black are correct, you only need 2 wires in the 6-pin white. From what I can see in the photo, you only need pin3 (grey - ground) and pin4 (green - 5v or 3v). You will also need to put a jumper wire in the power supply 24-pin main connector from grn #16 to black common (if not already done). Then it is more likely it will work.
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