MacBook Pro mid 2012 820-3115-b power up issues and burnt chips

Discussion in 'MacBook Pro' started by Scouselad, Aug 29, 2016.

  1. Scouselad, Aug 29, 2016
    Last edited: Aug 29, 2016

    Scouselad macrumors newbie

    Aug 29, 2016
    hi all,

    Sorry if this information is else where on this site as I'm unable to find anything regarding this issue I'm having hense me asking this question.

    So i was using my MacBook yesterday and all was well untill it just turned off on me completely ... At first I assumed the battery had died but then I seen I had the mag safe charged connected so it couldn't be that, then I noticed the light on the charger was solid green indicating that the battery was charged.

    I pressed the power button with nothing happening, I pressed the battery level indicator on the side whist it was connected to the charger and it showed 3 LEDs, I dis connected the charger and pressed the indicator again and nothing.

    After googling a few things and trying various different ways of resetting smc pvram etc nothing was working, so I decided I would try a hard reset by disconnecting the battery from the board which did not work, while I had the bottom off the MacBook I was checking the board for anything that didn't look right when I seen that there was 2 chips or possible resistors that were every discoloured .... Green ish, I thought this may be the problem which I assumed I will need to replace the Logic board or send away for repair at this point, just before I give up I tried (with the bottom plate removed) disconnecting the battery and connected the charger then had somebody hold down the power button whilst I connected the battery again.... The results where that the 2 green discoloured chips on the board, resistors I assume, went bright orange then a puff of smoke but ahhh, but then the MacBook sparked in to life and all is working absolutely fine with theses resistors burnt out on the board.

    I have used the machine for several hours doing various tasks and all is ok, as good as it's ever been

    So my question is, what are these resistors/chips responsible for and are they likely to cause a issue with the machine going forward ?

    Hopefully you can see the components on this picture.

    Any help much appricatated.[​IMG]
    Thank you.

    Here is what the chips looked like before then went orange and smoked up
  2. iMacC2D, Aug 29, 2016
    Last edited: Aug 12, 2017
  3. Jilly Bowman macrumors member

    Jilly Bowman

    Feb 2, 2017
    --- Post Merged, Feb 2, 2017 ---
    They are 10uF Capacitors used to decouple one of the power rails. Luckily when they fried, they went open circuit thus removing the short on that rail. You can probably work fine without them but it is possible that they may indeed short again in the future but very unlikely.

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