No power to logic board

Discussion in 'MacBook Pro' started by theath6123, Dec 30, 2012.

  1. theath6123 macrumors newbie

    Joined:
    Dec 28, 2012
    #1
    I have Macbook pro (mid 2009) that will not power on. It will not jump start or start using the "bypass" method. The magsafe and battery are both good (tested on different machine). However the magsafe stays bright green with the battery in or out. It seems to me that the logic board is not getting power. Is there a fuse or anything that could blow and cause these symptoms?
     
  2. justperry macrumors 604

    justperry

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    Location:
    In the core of a black hole.
    #2
    Go to ifixit.com, they have guides there on your model, you could look if it has a separate power board, I think it does but not sure.
    If this is the case you then could try to find a replacement board on Ebay.

    Which size, 13-15-17"
     
  3. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #3
    13. Are you referring to the Magsafe board? If so then it is separate. But it is not working on battery either and I know it has a good charge.
     
  4. justperry, Dec 30, 2012
    Last edited: Dec 30, 2012

    justperry macrumors 604

    justperry

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    #4
    If the battery is connected to that board you still have a chance it is not the logic board.
    I will look myself on ifixit.

    Edit: Did you try a SMC reset?

    Edit again: No it is connected to the Logic board and the Power board is too small to have anything controlling power management so it is the Logic board or the SMC reset might work.
     
  5. Dadioh macrumors 65816

    Dadioh

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    Location:
    Canada Eh?
    #5
    Did this suffer a liquid spill?

    Green LED means that the SMC is powering up and is getting a signal from the charger IC ISL6258 that it is also getting power. That rules out the magsafe (or DC-in) board as the culprit. There is a white fuse in the lower right section near the battery connector that is the 12V fuse for the logic board. Check if you have 12V on both sides of that.

    Otherwise, there are a myriad of potential issues related to non-charging and non-starting symptoms. You could try my (long) thread on various logic board issues. It is a long read but you may find something useful in there.

    http://forums.macrumors.com/showthread.php?t=1122338

    Good luck.
     
  6. justperry macrumors 604

    justperry

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    #6
    Oh, I remember your former thread now, what did you do, used a heat gun or baked it in an oven?
    You should check all connections, maybe you didn't connect all of them or not securely.
     
  7. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #7
    No water spill. I was having issues with the GPU. I put it in the oven for 7:30 at 385. I reassembled everything perfectly. I even took it apart and put it back together with no luck. Right now i have the board back out and I am trying to diagnose that way.


    I did try the SMC reset before I took it back apart.
     
  8. Dadioh macrumors 65816

    Dadioh

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    #8
    The oven method is basically a board level solder reflow to repair bad solder joints. I rarely use this method unless I have very good reason to believe that it is solder joint related.

    Have you tried the SMC bypass method?

    1) Disconnect battery and charger
    2) Hold down power button
    3) While holding power button connect charger
    4) Wait a few seconds
    5) Release power button
    6) Press and release power button

    This bypasses the checks that the SMC normally does on boot up and can sometimes allow the system to boot to allow further diagnosis such as running Apple Hardware Test (on the applications install DVD).
     
  9. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #9
    yes I tried the bypass trick. It still would not start.

    ----------

    I get no voltage on either fuse.
     
  10. Dadioh macrumors 65816

    Dadioh

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    Canada Eh?
    #10
    How are you measuring the voltage? One probe should go on a ground point such as the exposed areas where the logic board is fastened into the case. The other probe goes on the fuse. It would be very odd indeed to not have 12V on at least one end of the fuse if you have a green light on the charger.
     
  11. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #11
    Lol it was a cheap volt meter that only measure 60+ volts. I wil get another today and post back my results
     
  12. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #12
    I got a nice multimeter now. Both fuses are measureing good. I got 12 @ the battery and 16.5@ power board. What should I measure now?
     
  13. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
  14. Binomio macrumors member

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  15. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #15
    Yes it will not jump start or even start by doing the bypass method

    ----------

    I have two good batteries verified in my other mbp. One is fully charged the other is about. The magsafe stays bright green no matter which is in the unit. The charger indicator is the only thing working
     
  16. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #16
    I took measurements from various places on the board and everyrhing seems to check out except the 470 resistor near the top of the board. Its reading 0 ohm...
     
  17. theath6123 thread starter macrumors newbie

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    Dec 28, 2012
    #17
    Nevermind. I was reading it wrong
     

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