Mac Pro 2009 Issues after NorthBridge Repair

Discussion in 'Mac Pro' started by Jabaar, Apr 25, 2019.

  1. Jabaar macrumors newbie

    Jabaar

    Joined:
    Apr 6, 2019
    Location:
    Ontario, Canada
    #1
    Hello everyone! I was doing an upgrade on my 2009 Mac Pro upgraded to 5,1 and noticed the North Bridge was wiggly, so I used some screws, sprints and nuts to re-secure it into place after getting rid of the regular Apple Northbridge holders. However, upon installing the new CPUs and booting - the GPU fans blast at full speed, I am greeted by a black screen and there is no chime. The CPUs I am using are Xeon x5670s.


    Now, I noticed that if I only have CPU A installed, the system boots and works well, it is only upon installation of CPU B that this occurs. I’ve used both CPUs in socket A to verify that they are working, so I’m stumped as to what is causing this problem. The pins seem to be in great condition from what I can tell.


    If anyone can shed some light on this it would be greatly appreciated!
     
  2. h9826790 macrumors G5

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    Most like you can't get the tension right on heatsink B.

    As long as you can boot with CPU A only. I don't think that's NB related (especially you can check the NB temperature after you boot with CPU A only).
     
  3. Jabaar thread starter macrumors newbie

    Jabaar

    Joined:
    Apr 6, 2019
    Location:
    Ontario, Canada
    #3
    The only thing throwing me off honestly is the fact that the Gt 120 I have temporarily in my system blows its fans at full speed, and there are no ram lights. I’ll likely keep trying to get the tension correct soon.
     
  4. MIKX macrumors 6502a

    MIKX

    Joined:
    Dec 16, 2004
    Location:
    Japan
    #4
    Jabaar

    I recommend this if you use the "Nut & Bolt" Northbridge heatsink technique.

    ======================================
    Nut & Bolt Norhbridge technique ( of course, clean and reapply thermal paste. )

    From the Northbridge heatsink top . .

    1. M3 bolt ( from memory length 20mm ).
    2. 1/2 of a ballpoint pen spring.
    Northbridge heatsink top

    Northbridge heatsink bottom
    3. Non-conductive M3 washer
    4. M3 Metal washer
    5. M3 nut
    6. M3 nut = to lock the upper M3 nut at about the same tension that the spring
    of a plastic rivet would normally be set at.
    ( gently pull one of the OK rivets to get a 'feel' for getting similar "rivet spring tension" to allow for " expansion -contraction ". as the Northbridge heats up - especially in summer.)
     
  5. Jabaar thread starter macrumors newbie

    Jabaar

    Joined:
    Apr 6, 2019
    Location:
    Ontario, Canada
    #5
    Ended up cleaning everything and re seating the north bridge and still no luck, CPU A works like a charm, cpu B is being annoying and doesn’t seem to want to properly work. May play around with the pins and see if they may have gotten pushed down and I didn’t notice it.
     
  6. MIKX macrumors 6502a

    MIKX

    Joined:
    Dec 16, 2004
    Location:
    Japan
    #6
    Don't give up. . write down how many turns you do for CPU B - a " little " tight seems to be OK.
    Much easier on a 5,1. Tighten diagonally.
     
  7. Jabaar thread starter macrumors newbie

    Jabaar

    Joined:
    Apr 6, 2019
    Location:
    Ontario, Canada
    #7
    I’ll keep trying, I’ve done this upgrade plenty of times before and just when I think I have the right tightness and the NorthBridge is fine it all goes south, I shall keep persevering!
     
  8. Jabaar thread starter macrumors newbie

    Jabaar

    Joined:
    Apr 6, 2019
    Location:
    Ontario, Canada
    #8
    Alright little update - put in the original CPUs and still no luck, likely something to do with the socket, as the cpu light is on when I have cpu a installed and cpu b simply sitting in the socket. Will continue trying to figure it out, if anyone has suggestions feel free to drop them!
     

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7 April 25, 2019