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Thread: IBM 7043 (43P-150) Power Supply

  1. #1

    Default IBM 7043 (43P-150) Power Supply

    The power supply of my IBM RS/6000, type 43P-140, model 7043-44 broke down.
    The PSU is a Delta Electronic DPS-250DB A Rev.2

    I already had it open, hoping to see some visual damage. Nothing. The small glass fuse is also ok.
    As I'm no expert in electronics but can solder, I would like to try to replace it with a AT or ATX PSU - if possible.
    My plan is to simply cut the wires with the connectors from the old psu and solder them to the new PSU.

    Has anyone the pinout of this PSU or of the mainboard connectors? Or does anyone know which cable color means which voltage, and how the soft-power-on function works?
    I've attached a picture of the mainboard connectors.

    mainboard connectors.jpg

  2. #2
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    Default

    You're in luck. I DLed the IBM maintenance manual for the 43P-140 and -150 when I got my -140.

    ftp://csiph.com/incoming/timc/PDFS/I...0/sn329080.pdf

  3. #3

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    Quote Originally Posted by WBST View Post
    You're in luck. I DLed the IBM maintenance manual for the 43P-140 and -150 when I got my -140.

    ftp://csiph.com/incoming/timc/PDFS/I...0/sn329080.pdf
    It only describes where the connectors are, nothing more.
    Thank you anyway.

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  5. #5

    Default Solved - probably

    As I did not find any information on the internet I disassembled the broken PSU, hoping to find out what voltages all those wires are supposed to carry.
    Luckily people at Delta Electronics printed nearly everything on the PCB, and I was able to build an adapter cable using a standard ATX PSU.

    The PSU IBM is using is basically something in the middle between a old AT PSU and a ATX PSU.
    The PSU has the two usual AT mainboard power connectors, two additional connectors for 3,3V+GND, and a small connector for V5 stand-by and soft power on function.

    So I bought a cheap ATX-to-ATX extension and a ATX-to-AT adapter cable and proceeded like this:
    - IBM's "AT mainboard connectors" are wired regularly, the same as with any AT computer, but have slightly modified plugs: They have less "noses", so I had to file off some on the AT plugs of the AT-to-ATX adapter.
    - Plugs P10 and P11 have +3,3V (green) and GND (black) - I took +3,3V from pins 1+2 of the ATX PSU and GND from a black wire that's available
    - P9:
    - red : +5V -> connect to the purple "5V SB" at the ATX PSU
    - purple: Power on/off -> connect to the green "PS_ON" wire at the ATX PSU
    - black: GND -> use any black wire at the ATX PSU
    - brown: labeled "EPOW", was connected to the small control PCB in the original PSU -> no clue, seems not to be necessary. I left it unconnected.
    - gray: labeled "VFAN" and was connected to the + pin of the PSU fan -> I left it unconnected.

    This seems to work: The machine powers on and starts the usual self test. After some seconds it gets stuck with "E309" in its small display. But I believe this is a different issue.

    The pictures shows the ATX extension at the top, at the bottom is the AT-to-ATX adapter.
    I've pulled all wires out if the ATX extension that are not used by the AT-to-ATX adapter, and could use all of them, except 3,3V/sense (pin 11). Maybe that's "EPOW"? Currently I'm too worried to try that out.
    I cut P9, P10 and P11 from the original PSU and soldered them to the pulled-out wires of the ATX extension cable.
    IBM 43p-PSU-Adapter.jpg

  6. #6

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    Quote Originally Posted by citronalco View Post
    - P9:
    - red : +5V -> connect to the purple "5V SB" at the ATX PSU
    - purple: Power on/off -> connect to the green "PS_ON" wire at the ATX PSU
    - black: GND -> use any black wire at the ATX PSU
    - brown: labeled "EPOW", was connected to the small control PCB in the original PSU -> no clue, seems not to be necessary. I left it unconnected.
    - gray: labeled "VFAN" and was connected to the + pin of the PSU fan -> I left it unconnected.
    IBM 43p-PSU-Adapter.jpg
    Update:
    - "VFAN" is the power to the case fans -> connect to 12V (yellow)
    - "EPOW" means "Early Power Off Warning" -> connect to GND (black)

    And I fixed "E309" error: This indicates a memory error. I cleaned the contacts of the RAM modules with fine sandpaper, error gone.

  7. #7

    Default

    I just stumbled over this thread as I am facing a similar problem at the moment. This was quite helpful!

    The only thing that I am wondering: Did you ever measure the power draw on the green 3.3V-bus? I am especially wondering about this as they are using a total of 6 wires for that. And the original PSU states that the 3.3V bus can deliver up to 30A.

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    Quote Originally Posted by citronalco View Post
    Update:
    And I fixed "E309" error: This indicates a memory error. I cleaned the contacts of the RAM modules with fine sandpaper, error gone.
    A rubber eraser or contact cleaner would be more gentle for the contacts. Were these gold plated or tin plated?

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