HP z400 requires rewiring system-board power?

I own an HP z400 workstation. I want to use a high-end graphics care that requires more power than what the machine comes with. However, it seems that putting a third-party ATX-style power supply into the z400 won't work because HP has some propriety things going on with the power supply.

Check out the first sentence in this z400 data sheet on the HP site: http://www.hp.com/united-states/personal_again/datasheets/the z400_ds.pdf

And the middle of the "Innovation..." paragraph on page 1 of this z400 info document: http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA2-4464EEE.pdf

Also, check out the “HP WattSaver” section at the bottom of this page on an HP "UK" site: http://h41111.www4.hp.com/new_workstations/uk/en/profinno_environment.html

And you can see the phrase “Power Supply – 475 watt custom power supply - (Wide Ranging Active PFC)” if you search for the word “Custom” on this Russian HP z400 info site: http://www.server-unit.ru/tekhopisaniya/workstations/hp-z400-workstation

One thread on another forum suggests that a home-made wiring adapter that rewires the connections for the system-board power plug can do the trick: http://forum.corsair.com/forums/showthread.php?p=457289#post409472

So, my questions, please, are:

Is there any chance we're losing something important with this wiring adapter in terms of the "custom" power features of the z400?

Or are we pretty sure it will work just the same as the supplied power supply?

And if we're sure it will be okay, any chance I can please get a more explicit and/or updated explanation of how to make the adapter and what it's doing, so my tech guy can take it from there?

Thanks a million!

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More about z400 requires rewiring system board power
  1. Have you checked out any after market HP compatible PSU's? I'm not sure if there would be any for your particular model, but there are some out there for say, Dells. Hence, why I would assume there has to be someone out there who makes the PSU that you are looking for.
  2. buwish said:
    Have you checked out any after market HP compatible PSU's? I'm not sure if there would be any for your particular model, but there are some out there for say, Dells. Hence, why I would assume there has to be someone out there who makes the PSU that you are looking for.
    That seems like a great idea to me, too. I did do quite a bit of searching on the web and nothing came up. I used various search strings including some with the phrase "third party" but never used "after market." Do you think that will make the difference? Any other ideas on where to look to find one?

  3. Use 2 power supplies, an HP and a regular ATX.

    Using a Second Power Supply

  4. If you tell us how many amps you have on the 12v rails and list all your hardware we can calculate if the power supply is sufficient for your needs.
  5. You can get a dedicated video card power supply and mount it in a 5.25" bay.
    For example:

    Thermaltake ToughPower Power Express W0157 Video card power supply - 450 Watt

  6. You totally solved my problem for me. I'm using the HX750W externally as a second power supply to power the video card.

    The position of the PCI slots in the machine is such that the video card and the empty slot openings are down near the floor. I ordered two 12" PCI-Express power extension cables from NewEgg that will result in a few inches of cable sticking out of the back of the machine for easy connection/disconnecting.

    And if I had any questions about turning on the power for the HX750W with the creative control of the 24-pin plug, well, Corsair made that really simple for me with an item on their website. See this item from their "tips" page for power supplies that come up when beginning to submit a support ticket (which tells me which pins to jump and that it's totally safe):

    Q: How can I test my power supply?

    A: You can easily test a power supply for functionality with a simple paperclip. First, disconnect all the cables from your motherboard and other devices, but leave the power supply plugged into the wall. Next, bend the paperclip until you have a U shape. Find the 24-pin ATX connector and plug one part of the paperclip into the socket where the green wire ends, and the other end into the socket where a black wire ends. Make sure the power switch on the back of the PSU is on, (should be the I symbol) and the fan should spin up. If it doesn’t, your power supply may be bad.

    (Note that I spoke to ThermalTake. They no longer make a 450W internal power supply. Only a 650W, and it takes up two bays. I need all my drive bays for what I want to do. It also has an adapter to turn on power that goes in-line with the 24-pin system board power cable, and I don't know how HP has modified the pin-out, so these are two more reasons to go with the external solution instead. But it was a good idea.)

    Thanks so much! You saved me from having to build a whole new machine!

    Now, having said all that, I still would like to take you up on your offer to help me determine if the existing power supply in the machine is enough. I learned today that your asking about “amps” is right on the money and that everyone else asking about wattage was missing the point. Check out this other item on the Corsair “tips” page for power supplies:

    Q: My new video card says it needs a XXXX Watt PSU, is this going to be good enough?

    A: Ignore wattage for a minute and find out the Amps that your video card requires on the +12V rails. Match that number against our power supply, and you will more than likely find that the Corsair HX series provides more than enough power.
    So, here’s a picture of the label on the power supply that came in the machine (I don’t’ know how to translate to answer your question and I can’t find anything online, so this image is the best I can do, which I threw up on my website):


    The hardware that’s in the machine is:

    • Intel Xeon W3520 2.66GHz/8M Cache Processor
    • RAM 8GB DDR3 1333
    • 5 hard drives: Samsung SpinPoint F3 1TB
    • DVDRW(Light Scribe)
    • I can’t really elaborate on the cooling fans, other than there are one for the CPU and one for the case.
    • And of course the nVidia GTX-470, which I assume you can find the actual "amperage" requirement on a lot faster and more reliably than I can (but I'll look when I get back to the office later if you need me to).

    Thanks so much!!!

  7. The power supply that came with the machine is enough for the entire system with the new video card also.
    You need 35+3 amps, you have 38 amps.
  8. Wow! That is revealing news.

    Forgive me for asking but is this a pretty reliable conclusion? It seems like at best I'm right on the brink. I've been warned by others (who I realize vary in really valid knowledge) that if I surpass the limit I could corrupt the OS and data and burn out components.

    I'm thinking it's worth the extra two plugs on the back for the second PSU. Now that I own it and the wiring is done and it's working fine, maybe it's "a little better" to keep it in?

    Can I at least ask, what are my real-world risks if I'm a tad beyond the limit (by, say, inadvertently adding one more small device in the future)?

    Thanks again!
  9. You are at the limit with that power supply, if you want to feed the video card with it also. The extra power supply does not hurt, if you are planning on adding components. By exceeding the limits of the power supply, you could blow a component in the system like others say.
  10. FSP also makes an auxillary 450W PSU that would work in your situation ---- NewEgg Linkie
  11. Now I've been having issues with the high-end video card I put in there.


    I think it's time to build a new machine, and let that "workstation" just be a business desktop.
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