Identifying broken chip and pin on LB, related to keyboard

Discussion in 'MacBook Pro' started by runlos, Jan 11, 2014.

  1. runlos macrumors newbie

    Jan 11, 2014
    Just cleaned up a A1286 mbp mid2010 from a spilled cup of tea. The machine works except the keyboard+power. have tested two different keyboards, same issue, i figure it must be the logic board. So i cleaned it up real nice, but found a chip near the keyboard connection socket which looked like it had som residue covering it. After i had removed the residue, the chip looked like it was missing a pin. On this pics from ifixit the chip has all pins, on my LB ones is missing. i have marked which pin is missing. see pic

    Does anybody know what the chip do or controlls? Is there somewhere i can get a datasheet of the LBs architecture?

    Attached Files:

  2. old-wiz macrumors G3

    Mar 26, 2008
    West Suburban Boston Ma
    You will find it hard get the LBA datasheets - these are Apple proprietary and not generally available. They can be found, but Apple tends to track them down and have them deleted.
  3. simonsi macrumors 601


    Jan 3, 2014
    Spilling tea on it won't remove a pin from a chip...
  4. iphonerepair12 macrumors newbie

    Jan 2, 2014
  5. runlos thread starter macrumors newbie

    Jan 11, 2014
    well, the tea didn't remove it, i did... sticky residue, probably sugar had stuck around the pins on the one side. it was corroded or rusted. had to remove it with plastic toothpick. now there's missing a pin.

    I have now powered up the machine. now the keyboard works, except ctrl-key, left shift-key and the power-key. the power-key just shuts the machine down cold immediately, but won't power on the thing. I have to disconnect the battery and connect it and power again for it to start up...


    do you know if this chip has anything to do with my ctrl-key, left shift-key and the power button not working?(power button will shut the machine down, not start it) i would assume so, but have no clue.
  6. iphonerepair12 macrumors newbie

    Jan 2, 2014

    The pin which is broken is connected to the keyboard connector and to PP3V42_G3H. It is possible that this is the reason why your mac won't power on by using the keyboard button.
  7. runlos, Jan 12, 2014
    Last edited: Jan 12, 2014

    runlos thread starter macrumors newbie

    Jan 11, 2014
    I managed to solder a connecting pin back on the chip, and now the power button works, thumbs up!

    But the left shift-key, opt-key and ctrl still doesn't respond. Do you know which pins on the keyboard connector are related to these keys?

    edit: also f1 and f2 does not respond after the soldering..
  8. iphonerepair12 macrumors newbie

    Jan 2, 2014
    If you are sure you are using an 100% working keyboard you can start checking the pins on U5725, U5726, U5727 and U5703. That are the IC's on top of the keyboard connector (U5703 is the one you already fixed). If you cannot find any missing or corroded pins on those components then also check U5701 it is on the left of the keyboard connector.

    But the best thing to start with is to make sure you are using an good working keyboard, and clean the keyboard connector on the logicboard with 99% IPA.

  9. Villydk macrumors newbie

    Apr 21, 2015
    Hi, sorry for digging up an old thread, but I will ask before making my own. Have you fixed your problem? My power, left shift, ctrl,alt keys doesn't work as well, even when I replaced the keyboard. Any ideas/tips?

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