[Noisebridge-discuss] Mac Book Pro + Water = Sad Mac Keyboard

John Adams jna at retina.net
Sat Mar 3 14:48:53 PST 2012


On Sat, Mar 3, 2012 at 2:31 PM, Jared Dunne <jareddunne at gmail.com> wrote:

> NB-
>
> My gf spilled a decent amount of water on my old 17" MBP's keyboard the
> other day.  I was wondering if people with experience with similar
> incidents with A1212 17" MBPs could share some tips.
>
>
That sucks.

The next day I put back in the battery and powered it up.  It worked fine
> except some of the keys were "stuck", meaning it was acting like they were
> held down, namely some combination of shift, control, and command.  The
> behavior was that when I typed everything was in all CAPS and numbers were
> punctuation, etc.  Also when I clicked links in the web browser they opened
> in new windows.


The command key is shorted, or lines running from it are.


> I've removed the keyboard again and removed the keys that were still
> having issues.  There isn't anything obviously afoul with them, aside from
> there being some dusty/cloudy appearance between the layers of transparent
> plastic housing the connections to/from the nubs that get depressed, which
> isn't dramatic different than the appearance surrounding the working keys.
>


That's called corrosion and it's what happens when water hits a live
circuit. The water mixed with whatever junk was in your laptop and formed a
nice fluid with resistance and all sorts of other lovely properties.

One trick I've used in the past is a pencil eraser to remove corrosion from
the mylar traces on the plastic, but really, you need a new keyboard.

Questions:
> - Could the behavior be caused by a incomplete connection of the ribbon
> cable?  Or would that cause boot errors or all-or-none behavior?  Tips on
> getting that ribbon cable in snugly despite the lack of slack in the cable?
>

What's on that cable is the keyboard matrix going to the controller chip.
You could have shorts there, or worse yet, the water has shorted the
keyboard controller chip's inputs. rendering the chip useless.


> - Did I screw up by rinsing it off?


Possibly There's more in city water than just water. If you'd rinsed with
distilled water here or even a mild alcohol, you may have been better off.


> Alternatively, did I not go far enough in my rinse?
> - Any other tips on what I should do next?  Clearly I can buy a
> replacement, but I'd like to eliminate the possibility of repair before
> doing so.


With things like keyboards and mice, I'm always of the opinion that they're
unfixable unless you're very lucky. ifixit has your keyboard for either $69
or $99 depending on model and it sounds like you've already wasted enough
time on this problem. Pony up.

-john
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