I bought a HP ProLiant DL180 Gen9 server in 12 LFF (3.5-inch) HDDs configuration. Now I'd like to put two additional 2.5-inch SATA HDDs inside the case to serve as system drives.

As a configuration with 12 LFF HDDs, this server has a P840 PCIe card that provides SAS/SATA connectivity for the whole HDD backplane. An integrated B140i SATA controller is to be used for those two additional 2.5-inch HDDs.

The remaining part of the puzzle is to somehow provide power to those two additional HDDs.

Some DL180 models can be stuffed with an optical drive (though this one isn't, but the system boards are/should be the same). Documentation shows that the optical drive power and the hard drives power come out from the same port (go back 3-4 pages). The port and the connector are here

Unused Pins


Judging by the official HP documentation and by having five unpopulated pins, I'd say that those exact five pins provide power to the optional optical disk drive.

My actual question is what's the function of unpopulated pins in the 20-pin connector? I need to find +12V, +5V and two GNDs. A friend of mine and I have disassembled the whole casing, took the system board out in hope of finding the power lines on the bottom side of the board, but it looks like they are in some middle layer. The last resort is to find pin-out by using a voltmeter, but I don't know if I could make something let out the blue smoke :)

Advices? Hints?

Thanks in advance,

  • 1
    20 pin ATX PSU pinout – uint128_t Feb 9 '16 at 17:43
  • Nope.. pinouts.ru/Power/atxpower_pinout.shtml The populated pins don't match 20-pin ATX PSU pinout. geewid.info/hp/close-up1.jpg geewid.info/hp/close-up2.jpg – geewid Feb 9 '16 at 17:48
  • 1
    Not ATX then. But regardless, red will be +5V, black GND, and yellow +12V. A voltmeter will tell you instantly. – Tom Carpenter Feb 9 '16 at 17:51
  • That's true... But please check the last sentence. I'm not an electronics expert. This port is meant to give out some power. Is there a chance of screw-up is it receives power (current)? – geewid Feb 9 '16 at 17:54
  • You can safely measure the pins with a voltmeter. Make sure the voltmeter is set to measure volts. – uint128_t Feb 9 '16 at 17:55

The idea for matching power supplies is you match the voltage and then the current, the power supply must be able to more current than the load needs or you will have a 'brownout' and the voltage will go lower than its intended level. Get a pinout of the motherboard with the voltages marked. If you cant find a pinout for that board then see if it follows and industry standard and find that pinout. Once you have that you can then find a supply to match it. If you want to check the voltages of the supply use a volt meter. You might have to put a load on the supply to get it to turn on, or use the enable wire.

The probable reason for the underpopulated pins is the engineers already were using that connector in another design, and it takes time and effort to buy and design with a different connector, so they went with the one they already had (I have unused pins on a lot of connectors). Either that or they wanted to save ~5-10 cents per a unit on the cost of the PSU wire since they probably aren't using those voltages.

  • Well yeah... It's a "standard" 20-pin ATX connector, repurposed by HP for this "drive power connector" as they call it. I couldn't find any similar pin-out for that 20-pin connector. There are some pin-outs available online, but all of them are for older HP ProLiants (generation 6 and older). Thank you for the tips. – geewid Feb 9 '16 at 20:40

Mystery solved. The voltmeter gave the following results:


Thanks everyone for help!


You can see a picture here for the pinout you'll need: http://partsurfer.hpe.com/ShowPhoto.aspx?partnumber=782466-001

  • 1
    That fails to answer the question because the linked image does not contain a pinout of the connectors. – bwDraco Feb 15 '16 at 2:36
  • Granted it is potato quality, but those are the 4 pins you'll need to use, red is +5, yellow is +12 and the two black are gnd... You can then either cut & solder or trace them to the BP1 connector and crimp the sata power into a 10pin atx plug. – Paul Feb 15 '16 at 3:09

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