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Mid 2010 Model A1278 / 2.4 or 2.66 GHz Core 2 Duo processor

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Odd Keyboard Characters after "accident".

Hello good people!

So far this site has just about got my out of the woods after almost losing my Macbook. Let's just say my cat urinated on the keyboard.. And killed it.

I disconnected everything, took all the internals out and cleaned with rubbing alcohol. Let the battery stay unplugged for a few days to let die whatever bad charge was in the system. Turned it on and hurray it is alive. (Thought I'd condense this and not include the hours of frustration and ripping my hair out.)

When it powered up all was well except the keyboard didn't work at all. So I cleaned the zif connector due to possible but unseen corrosion and now the keyboard is alive.

My problem is that everything I type now shows up on the Mac as some weird characters like this: ```££

I turned on the keyboard viewer to see what that Mac was interpreting and when I press a button the correct one does show up on the viewer.. Weird!

I'm thinking it is due to a stuck ALT key.

The weirder thing is that when I click on a letter in the viewer such as A to use the viewer to type.. The weird character is still showing up and it does not show the alt key as being pressed down.

I'm stumped! Is this a software issue that can be fixed? Or hardware due to what happened?

I checked the language and keyboards and such and the only thing selected is United States.

Thanks for any possible help!

Answered! View the answer I have this problem too

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I think the keyboards wiring is messed up by your pets accident.

You can try using an external keyboard (USB) to prove if it's a software thing (I doubt it).

I think its time to replace the upper case assembly. Follow this IFIXIT guide: MacBook Pro 13" Unibody Mid 2010 Upper Case Replacement. A used part is around $140 US.

The problem you face here is the corrosive effects of the cats urine as over time it will slowly eat though the copper traces of the keyboard switch pad. I'm sure you didn't take the whole keyboard apart here (50 some odd screws or rivets).

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I think my USB ports are shot though to.. Tried to plug in an iPod and it said it turned the USB off because of too much power consumption?

If I got a Bluetooth keyboard would the correct characters show up when typing do you think?

Just wondering because when I click the characters in the keyboard viewer to type the weird characters still appear.


The keyboard viewer is reacting to the mis-cue of what the keyboard is telling it so it makes sense it is showing the wrong key. By using a different keyboard input device was a way to prove to you the issue was hardware not software. Sure a BlueTooth will also work here. But your root issue is the upper case is damaged.


Given the USB ports are having problems as well it sounds like your logic board got hit too. In any case you'll need to dissemble the entire system to swap out the upper case so you might as well give the logic board a good inspection for damage and clean it. To do that you'll need distilled water and a soft brush to scrub down the board. Be careful as the small components can be snagged and pulled off. Once you clean down the logic board with the distilled water go over it with a high grade isopropyl alcohol (85% or better). The alcohol will act as a dryer pulling out the water that has seeped under things. Even still you'll need to give the board a little warmth to finish drying out. Put it on a sunny window sill and let the sun do the work for a good day.


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The acid and liquid in cat urine may still be causing damage. Not just that: There are sugars in urine that can scorch if enough heat develops, burning the electrical traces. If the USB ports are also wonky, you may have more serious logic board issues. At this point, if you're still trying to use this damaged computer, you're just trying to get around the problem rather than tackling it head-on.

I'd suggest stripping the computer down again, and then washing all the circuit boards in anhydrous (i.e., water-free) isopropyl alcohol. It's available from electronics stores and specifically intended for cleaning circuit boards. Not rubbing alcohol, which is 50% water. I use a Tupperware-like plastic tub to make a bath, and then dunk all the stripped boards in that bath for a day or so. I keep a soft, dry toothbrush around to gently scrub the affected areas free of all debris; you'll want to include the peripheral sockets and the top case socket in that treatment.

This guide gives some general guidelines for washing and drying before reassembly:

Electronics Water Damage

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Definitely something I was considering and going to try tomorrow!

Now what would I do in regards to this to also clean the keyboard? And trackpad?


The link in adlerpe's answer works well when you have just gotten your system wet with water. The problem is most people let the system dry out so what was in solution is now a dried crust all over. Here we need to attack the problem a bit differently. We need to push the crust stuff back into solution so it can be washed away. Instead of using isopropyl alcohol we need to use distilled water. While this doesn't seem intuitive, water is the Universal Solvent so it will dissolve most of what is on the parts. The issue most people fear is water is bad for electronics. While tap, rain, pond, lake & sea water all are, distilled water doesn't have any of the stuff in it that kills electronics! Even still you don't want to soak the parts too long here and you do want to change out the water a few times.


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Cory will be eternally grateful.
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