A1342 MacBook - Intermittent start up

Discussion in 'MacBook' started by debaron, Nov 30, 2011.

  1. debaron macrumors newbie

    Nov 30, 2011
    Hi all,

    I have a problem with my Unibody white MacBook. I'd like to know if anyone would be able to help me fix it!

    It was involved in a very minor liquid spill - almost nothing - but now it won't power up all the time. I've investigated it as much as I can and am at the end of my knowledge now.

    The symptoms are this:

    Connecting the Magsafe works properly and charges the battery. On pressing the power button the light on the magsafe changes to green for a few seconds then back to orange (PMU Reset?) 80% of the time nothing else happens. The other 20% of the time on repeated pressing of the power button (sometimes in quick succession - sometimes just a standard press slowly and repeatedly) the unit *will* power up. Some keys do not function properly but backlight and everything else are fine.

    On a *single* press of the power button while running (this happens every time) the unit goes *straight off immediately*

    I have shorted out pins 5 and 29 on the keyboard connection and the same lack of regular power up is observed so I don't think there is a power button fault (and also because the power button will switch the unit off 100% of the time as above)

    The fact that the PMU/SMC appears to be being reset when pressing the power is significant but I don't know in what way. I initially thought the shift and alt and apple keys might be stuck down but it happens when the keyboard ribbon cable is disconnected too.

    It must just be an intermittent connection somewhere and hopefully not too serious as everything 'works' albeit occasionally!

    Can anyone give me a shove in the right direction? I am handy with a multimeter and have a reasonably good solder station. Perhaps some fuse/component testing if you'll tell me where to look?

    Many thanks

  2. McGiord macrumors 601


    Oct 5, 2003
    Dark Castle
  3. debaron thread starter macrumors newbie

    Nov 30, 2011
    Thanks buddy, but they'll tell me I need a new board at £xxx.
    Plus i'm not sure they're down with working on liquid damaged stuff.

    I reckon I can sort it given a bit of help!

  4. ibuyufo macrumors 6502

    Sep 22, 2007
    You won't find any miracles here since you do need a new logic board. There are no minor liquid spills. It either seeps onto the electronic components or not.
  5. ArchiMark macrumors 6502

    Feb 2, 2003
    Silicon Valley
    Too late now, but your best bet in such a situation was to immediately shut down MacBook....and assuming you could do that quickly enough (and lots of luck...), then next step would be give MacBook enough time to let liquid evaporate thoroughly before even any attempt to power on MacBook again...

    At this point, from what I've read you need some new hardware....you should either bring it to Apple Store as previously suggested or to your local Mac shop for examination....

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