Pentium Pro mainboard not working, please help!

Discussion in 'IBM' started by PetroffHeroj, Jun 4, 2005.

  1. PetroffHeroj

    PetroffHeroj Guest

    Hello, folks.

    Recently got a Pentium Pro mainboard; processor included, 4 72-pin SIMM
    slots, built-in audio (some Crystal) and MIO, and so on -- yer olde server
    brand from the middle of the 90's. The power supply wasn't included, neither
    was the case or any peripherals, except for the bus multiplexor: the board
    has only one EISA-lookalike slot, where you stick the multiplexor to get 3
    PCI and 2 ISA slots.

    After hooking the board to a usual AT power supply and sticking in a video
    card and some SIMMs, I turned that mess on, but nothing worked for me. One
    of the video cards kept giving some skewed retrace and garbage (anyway, it
    looked like dirty white diagonal stripes running down the screen), and
    others were just black. The keyboard didn't get init'd (stayed with LEDs
    on), the speaker was silent even after I took away all memory modules and
    later the video to see if BIOS complains -- the board was silent.

    Now, the funny thing is that, although having an AT power connector (vs
    ATX), it also features an extra one labelled "STD 3.3V". That one looks
    exactly like one of the two AT connectors and neighbours them closely. I was
    told it was, ahem, "optional". But the board originally used it (of course).
    But that power supply with an extra dangle is long gone.

    Could it be that the board is not dead, and I just have to get a power
    supply from a more or less similar brand to make it work? In that case,
    would any such power supply do or not?

    There are also a couple of connectors that might be crucial to the board's
    operation. One of them is in the line with the usual pins for speaker, LEDs
    and stuff, and is named "SW_ON/SLP" ("switch on/sleep", I guess), and has
    four pins. The other is 3-pin and looks exactly like a an-board fan
    connector; that one is labelled "S-OFF". May be I've got to short-circuit or
    pulse some of the pins on those to get the board alive?

    Any comments will be really appreciated. Pentium Pros were rare beasts even
    back then when people actually heard of them once in a while (1995-1997),
    and these days laying my hands on that board was a real miracle. Suffice it
    to say that it's the first Pentium Pro CPU I saw face to face :) The guy
    must have pumped iron a lot judging by its size ;) Anyway, it's no wonder I
    desperately want to see that thing working.

    So far all I got is that the CPU _heats_ somewhat after several minutes of
    (non-)operation. So may be the board is not dead after all?

    Thanks!

    Leonid
    PetroffHeroj, Jun 4, 2005
    #1
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  2. PetroffHeroj

    NuTCrAcKeR Guest

    that board may require EDO or FPM memory ... also might require 50ns or 60ns
    refresh on the DRAM.
    Yes, typically the PPro boards with the extra power header needed the extra
    power, although most of the old PPro boards were 5v on the mains.

    Did you try clearing the CMOS and giving it another go?

    What information do you have about the board ... are there any markings
    silkscreened on the board itself?

    - NuTs

    "PetroffHeroj" <> wrote in message
    news:...
    > Hello, folks.
    >
    > Recently got a Pentium Pro mainboard; processor included, 4 72-pin SIMM
    > slots, built-in audio (some Crystal) and MIO, and so on -- yer olde server
    > brand from the middle of the 90's. The power supply wasn't included,
    > neither
    > was the case or any peripherals, except for the bus multiplexor: the board
    > has only one EISA-lookalike slot, where you stick the multiplexor to get 3
    > PCI and 2 ISA slots.
    >
    > After hooking the board to a usual AT power supply and sticking in a video
    > card and some SIMMs, I turned that mess on, but nothing worked for me. One
    > of the video cards kept giving some skewed retrace and garbage (anyway, it
    > looked like dirty white diagonal stripes running down the screen), and
    > others were just black. The keyboard didn't get init'd (stayed with LEDs
    > on), the speaker was silent even after I took away all memory modules and
    > later the video to see if BIOS complains -- the board was silent.
    >
    > Now, the funny thing is that, although having an AT power connector (vs
    > ATX), it also features an extra one labelled "STD 3.3V". That one looks
    > exactly like one of the two AT connectors and neighbours them closely. I
    > was
    > told it was, ahem, "optional". But the board originally used it (of
    > course).
    > But that power supply with an extra dangle is long gone.
    >
    > Could it be that the board is not dead, and I just have to get a power
    > supply from a more or less similar brand to make it work? In that case,
    > would any such power supply do or not?
    >
    > There are also a couple of connectors that might be crucial to the board's
    > operation. One of them is in the line with the usual pins for speaker,
    > LEDs
    > and stuff, and is named "SW_ON/SLP" ("switch on/sleep", I guess), and has
    > four pins. The other is 3-pin and looks exactly like a an-board fan
    > connector; that one is labelled "S-OFF". May be I've got to short-circuit
    > or
    > pulse some of the pins on those to get the board alive?
    >
    > Any comments will be really appreciated. Pentium Pros were rare beasts
    > even
    > back then when people actually heard of them once in a while (1995-1997),
    > and these days laying my hands on that board was a real miracle. Suffice
    > it
    > to say that it's the first Pentium Pro CPU I saw face to face :) The guy
    > must have pumped iron a lot judging by its size ;) Anyway, it's no wonder
    > I
    > desperately want to see that thing working.
    >
    > So far all I got is that the CPU _heats_ somewhat after several minutes of
    > (non-)operation. So may be the board is not dead after all?
    >
    > Thanks!
    >
    > Leonid
    >
    NuTCrAcKeR, Jun 7, 2005
    #2
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  3. In article <>, PetroffHeroj wrote:
    >
    > After hooking the board to a usual AT power supply and sticking in a video
    > card and some SIMMs, I turned that mess on, but nothing worked for me. One
    > of the video cards kept giving some skewed retrace and garbage (anyway, it
    > looked like dirty white diagonal stripes running down the screen), and
    > others were just black. The keyboard didn't get init'd (stayed with LEDs
    > on), the speaker was silent even after I took away all memory modules and
    > later the video to see if BIOS complains -- the board was silent.


    This bit about the keyboard had me thinking "power supply problem" even
    before you mentioned the additional power connector. The simple reason
    being that the keyboard diagnostic isn't done by the computer but by the
    keyboard itself upon power-on (it gets confused with the POST tests
    simply because the computer is running these at the same time). If your
    keyboard lights are staying on it means that the keyboard isn't happy
    for some reason - if it works elsewhere it's almost certain to be its
    power supply that is causing this.

    --
    Andrew Smallshaw
    Andrew Smallshaw, Jun 8, 2005
    #3
  4. PetroffHeroj

    PetroffHeroj Guest

    Thank you, fellows, for responding with your helpful suggestions!

    I had trouble getting the answers though thanks to my ISP's news server
    quirkiness. It choked and disposed a good handful of articles into nowhere,
    and I only learnt about and got your replies recently from
    groups.google.com.

    Thanks again. I'll be sure to follow your advice and make an attempt to do
    something about the PSU. It's a lot better to have a PSU problem, however
    bad, than having a dead mainboard... of possibly jewelry value :)

    To Andrew:

    >> After hooking the board to a usual AT power supply and sticking in a video
    >> card and some SIMMs, I turned that mess on, but nothing worked for me. One
    >> of the video cards kept giving some skewed retrace and garbage (anyway, it
    >> looked like dirty white diagonal stripes running down the screen), and
    >> others were just black. The keyboard didn't get init'd (stayed with LEDs
    >> on), the speaker was silent even after I took away all memory modules and
    >> later the video to see if BIOS complains -- the board was silent.

    AS> This bit about the keyboard had me thinking "power supply problem" even
    AS> before you mentioned the additional power connector. The simple reason
    AS> being that the keyboard diagnostic isn't done by the computer but by the
    AS> keyboard itself upon power-on (it gets confused with the POST tests
    AS> simply because the computer is running these at the same time). If your
    AS> keyboard lights are staying on it means that the keyboard isn't happy
    AS> for some reason - if it works elsewhere it's almost certain to be its
    AS> power supply that is causing this.

    I didn't realise that, thanks! I erroneously believed the keyboard doesn't
    get init'd by itself on power-on, and it's only the BIOS that sends the
    internal diagnostics command to it; until that, I believed, the keyboard
    stays with LEDs on. This was plain wrong, as I proved myself by
    disconnecting and reconnecting the keyboard and watching it passing the
    diagnostics, blinking the LEDs momentarily, and finally sending 0AA.

    A good guy on EFNet said it's very, very likely that this board _requires_
    the additional wires on the third power connector in order to function
    properly, and that's why it doesn't want to get alive. Quite correlates with
    what you are suggesting.

    Leonid
    PetroffHeroj, Jun 11, 2005
    #4
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