How To Feed This Board?

I have a minor problem and it looks like this:

SBT2 Power Connectors

Those are the power connectors on an Intel Server Board SBT2, produced circa 2000. I can’t find the right thing to plug into them.

The 24-pin connector should be more or less regular ATX, but it’s not enough to power up the board (nothing happens when I short the power switch pins). I don’t know if the 10-pin connector is required to be used as well, or if perhaps the auxiliary connector in between has to be. It’s also possible that the board is simply dead, although there is no obvious damage.

Here’s what the entire board looks like:



That big thing which looks like it’s made out of cardboard is, in fact, cardboard. It’s a spacer installed in an unused CPU slot in order to achieve proper airflow in a chassis.

It’s obviously a big board with 64-bit PCI slots, 4GB RAM, two SCSI channels (U160 LVD and Ultra Wide SE), integrated graphics, and a management processor. The board takes up to two Pentium III Xeons with 133 MHz front side bus and is built around the ServerWorks ServerSet III LE chipset.


Intel SBT2

The manual mentions something about an SSI power supply. SSI (Server Side Infrastructure) seems to be, among other things, a power supply standard which is an offshoot of ATX and designed for servers. But where to find such a beast?

I don’t have a suitable chassis (such as Intel SC5000), so I can’t verify that the board works at all. Being a server board, the SBT2 doesn’t just power up—the BMC (Baseboard Management Controller) has to be booted up first, and only then can the rest of the system be powered. I have a suspicion that there might be a problem with standby power for the BMC, but that is just a suspicion.

Can this board be hooked up to a generic ATX power supply, and if so, how? If it requires a special SSI power supply, where to find one (that doesn’t cost an arm and a leg)?

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19 Responses to How To Feed This Board?

  1. A. Kohl says:

    Old boards of Apple’s Power Macintosh form 1995 to 1997 had the same connectors but lower power. SSI boards require at least 450 or 550 W.

    Last Specification for SSI Power Supplies can be downloaded here.

  2. erkko says:

    should be like all the server-style psu connectors dedicated to cpu power. most of them being 8-pin; regular desktop-atx-psu has 4-pin. what they all have in common – most of them will not power up without cpu 12v being connected; and pins on the side of the fixator clip are 12v, pins on the other side are ground. should be easy to test it with multimeter on the board itself. connect regular atx with its 4-pin 12v inserted into that 10-pin connector, keeping that fixator on the same side as the bigger one would have and it should power up, if there are no other issues.

  3. Krzyś says:

    Sorry for the obvious, but have you tried that? (second hit for googling SSI power supply pinout)

  4. Michal Necasek says:

    Intel’s own SC5000 chassis was sold with a 300W PSU, so it’s unlikely more would be needed.

  5. Michal Necasek says:

    The pinout isn’t a problem, that’s documented even in the board’s manual. What I’m looking for is an existing (likely used) PSU that will fit. I’m also not entirely certain what the power-up procedure is. As I said I’m not entirely certain the board is working, which makes any experimentation difficult.

  6. Michal Necasek says:

    That 10-pin connector is weird… it’s an “I2C Power Connector”. Most of the pins are not connected and there are I2C clock/data pins. It seems to be designed for telling the PSU what the board is doing. I just don’t know if anything has to be plugged into it.

    The power switch is also funny, the two pins are Ground and Standby +5VDC. I don’t know if it’s meant to be briefly shorted or if the pins actually need to be permanently connected for the board to come up. There is actually a separate power switch in a different connector.


  7. Krzyś says:

    But you didn’t mentioned connecting 4-pin ATX power supply plug to 10-pin SSI connector – the latter is said to be required (auxiliary one in-between is said to be optional). Since you’ve already tried plugging-in 24-pin ATX, maybe adding the 4-pin one will be enough to power up the board. I would try that first and if that failed only then go on sourcing actual ESP/SSI power supply.

  8. Krzyś says:

    OK, looked at the manual and apparently connecting +12V to I2C line (10-pin connector) isn’t a wise thing 😉

  9. Krzyś says:

    Shit! I’ve mistaken 10-pin I2C connector for 8-pin 12V one from … 😀

  10. Syllopsium says:

    SSI is a whole series of specifications, connectors, power supplies, cases and motherboard formats.

    The auxiliary power connector is quite rare on power supplies

    I had an Enermax which supports it – can’t remember which one, though. It was gold, but doesn’t match any of the ones I can immediately find. Might be easier to ask AMD dual processor users, where the connector was more commonly used. I used a Supermicro P6DGE/S (dual P3) that needed it.

    I suspect an SSI power supply is not required – it provides PSU monitoring, but usually isn’t essential. Once you have a PSU, the BMC is an invisible part of startup. I use a 2007 era Intel server motherboard with a BMC. Press the power button and it’ll start.

    What may be a problem is the lack of an SSI compatible chassis. Whilst it’s usually possible to hook up the various ATX motherboard connectors (power on, reset, HD LED) to an SSI pinout (SSI motherboards do not use well labelled standard ATX pinouts), this lacks the other SSI connectors such as I2C bus with external temperature sensors. The upshoot is that in a non certified chassis the fans may run at full speed.

    On some boards it is possible to re-program the BMC to run the fans at more acceptable speeds, but it’s not as flexible as using a proper case.

    Also note that the BMC may include a watchdog timer. If the OS does not report a successful load within the timeout period, the BMC will hard reset the board. It’s not been immediately obvious how to report success on the complex Xen/VM configuration I’ve been running, so I just disabled the watchdog temporarily.

  11. Octocontrabass says:

    It looks like you should be able to power that board with any ATX power supply, but there’s a catch: the power supply has to be able to run with no load on the 12V rail. Modern computers attach the CPU voltage regulators to the 12V rail, but that board connects them to the 5V rail. The power supply you’re using might consider the load imbalance to be a fault and refuse to power up.

    If you want to verify the BMC’s power, all you need is a cheap multimeter and a copy of the chip’s datasheet.

    Have you tried shorting the power switch pins on the Switch Interface Connector? Are all of the jumpers set correctly? Are you using the correct type of RAM?

  12. Michal Necasek says:

    I did see that page. What it describes doesn’t match either my PSU (which has a 24-pin connector already) nor the board (which has no 8-pin power connector). And yeah, the 4-pin 12V thingy from the power supply does fit into the 10-pin connector on the board, but it seems unlikely that it would do any good with the I2C pins 🙂 I suspect the 10-pin connector is strictly for monitoring.

  13. Michal Necasek says:

    I have the right RAM and did go over the jumpers. I should have mentioned right away that the PSU doesn’t power up (fan doesn’t spin), so I don’t actually expect the board to do much.

    The thing about 12V rail usage is interesting, and it could be an issue. Is there some easy way to verify if that’s an issue or not?

  14. Michal Necasek says:

    I suspect the auxiliary connector isn’t required and is intended to supply the PCI slots with extra juice (power-hungry RAID controllers etc.). But I don’t think it’s clearly documented whether it has to be connected or not.

    The thing about the power switch is that there are two, and I don’t know what’s what. There’s a switch in a “switch interface connector” (P27) but there’s also a separate “power on/off switch connector” (12N6). I tried looking at the SC5000 chassis manual but it wasn’t detailed enough.

    I have another Intel server board from about the same era (dual socket 370, SDS2 I think) and that one works in a more or less standard ATX chassis without trouble.

  15. Richard Wells says:

    The Intel documentation lists several unusual aspects for the power supply:

    The 6-pin AT style Auxiliary Power Connector needs to be plugged in with a 350w power supply. Yes, that means you need an exotic ATX v2 power supply for the 24-pin connector with an ATX v1 Auxiliary Connector. (SC5000_pg.pdf page 21) The connectors on the official power supply are labeled: P1 is the 24-pin motherboard, P10 is the Aux Power, and P13 is AUX SIG.

    The power supply has to provide 0.8 A of 5v in standby. Many ATX power supplies provide less.

    Also, the power supply signal connector needs to be connected or the system won’t boot.

    Last two items can be found in the Troubleshooting Guide (sbt2_tsg.pdf) on page 5.

  16. Octocontrabass says:

    The power supply should have ratings on a sticker. Generally, power supplies expecting large 12V loads will have a higher maximum output rating for +12V than the combined +3.3V/+5V rating. You might have to do some math: power (Watts) is current (Amps) times potential (Volts).

    Hard drives make pretty good test loads, if you’ve got any sitting around that don’t have important data on them.

  17. Ivan Veršić says:


    I think that I have same motherboard somewhere in the attic + correct PSU. Power supply is not of standard ATX dimensions (doesn’t fit in regular ATX cases, at least not without modification). Please contact me through e-mail if you’re interested.

  18. Michal Necasek says:

    Thanks! E-mail sent.

  19. MW says:

    Somewhere I have similar board. I’ve seen similar connectors on 2 more mainboards. First is IBM PS/1 tower with 486, then 5V is fed to AT-like one, second is IBM Power Series 850 (one with designers’ signatures on copper) in which it was PCI power connector.

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