Replacement of logicboard Mac Pro

Discussion in 'Mac Desktops' started by berazzi, Dec 6, 2017.

  1. berazzi

    berazzi New Member

    Dec 6, 2017
    Likes Received:
    Hi there,

    So im fairly new to the hardware of older Mac's but got my hands in a old Mac Pro 1.1 which was working fine, but definitely lacking power (it was the 2 x dual core version with only 4GB ram). So when i stumbled across some spare parts from a 3.1 I did not hesitate to buy it.
    So I took everything out, except the superdrives, harddrive, front panel board and the PSU and put in the following from the 3.1:

    - Logic board with CPU's
    - Ram risers with new dimms and 4 old dimms

    I obviously also fitted heatsinks and so on and attached the wifi antenna to the wifi card (which the 1.1 did not have).

    Now I made very sure I got all the cables right, so that should not be the problem.

    However when I try to boot it nothing happens except for the following:

    1. A VERY short click from somewhere near the front
    2. A flash from a red led somewhere in the vicinity of the Wifi card, so at the front of the logicboard. I have tried multiple times to see exactly where but I simply cannot see it because it is so fast.

    I have tried pressing the DIAG_LED when the computer having power and the only thing is that the STBY lights yellow which it as fasr as I can tell is supposed to do.

    Anyone have any ideas about what could be wrong or suggestions to what I should try? Also, if I left out any important info let me know.
    berazzi, Dec 6, 2017
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  2. berazzi

    Cory Cooper Moderator

    May 19, 2004
    Likes Received:
    Hello and welcome.

    The logic board isn't really a user-servicable part. Also, normally they cannot be interchanged within the various models.

    -Which exact model Mac Pro?
    -Where did you source the replacement logic board and RAM riser?
    -How did you attach the heatsinks?

    My guess is either the replacement parts are damaged, the PSU isn't strong enough for the new parts, RAM isn't installed correctly, etc.

    Cory Cooper, Dec 9, 2017
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