2.3GHz, 2.6GHz, or 2.7GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache.

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How can I diagnose a keyboard issue?

Background:

My laptop battery got to a state where it would not maintain charge very long, and recharges seemed abnormally hot and caused noticeable slowdown.

I decided to replace the battery, and I followed some tutorial instructions to open up the back and remove the battery after using isopropyl alcohol to help deal with the adhesive holding the battery in place. Even with the alcohol, it took some effort to pry off the battery, but I eventually got it replaced. I was careful not to touch the components above the battery, but it's likely some of the isopropyl alcohol got into the keyboard area.

When I booted the computer with the new battery, the built in keyboard seemed unresponsive, but then I realized some keys were responding with key presses or even combinations of key presses. I was able to sign in using a usb keyboard. I tried using the "Keyboard Viewer" utility to see which buttons were being registered for given key presses to see if there were any interesting patterns. It doesn't seem deterministic, if I press the same key in rapid succession it can act as different keys. Some keys seem more consistent than others. For example, pressing 'd' seems to consistently become all of (at once) 's', 'd', 'h', 'j'. However pressing 'a' sometimes becomes 'd' but sometimes becomes a chord of many ('~', '"', '`', '^', ''').

What I tried:

  • I tried resetting the PRAM by opening a terminal and rebooting after running: sudo nvram boot-args=”-p -r”
  • I tried removing and plugging in the keyboard ribbon connector.
  • I waited a day, to see if it would dry out residual isopropyl alcohol and change behavior.

My suspicions

  • I suspect that the isopropyl alcohol caused damage as the most likely explanation.
  • After that I would suspect damage to the ribbon connector from forcing out the battery. However, it was covered by the factory tape and didn't seem to be touched until I readjusted it to test if something was wrong.
  • I don't know much about PRAM, but someone suggested maybe replacing the battery corrupted metadata related to interpreting the keyboard.

Help

I'd like to know what I can do to further diagnose or treat the keyboard issue. For instance, if there are tests I can do to see whether it's an issue with the ribbon or the keyboard component itself. Ultimately I'd like to know if it is salvageable, even if it requires purchasing and replacing the keyboard. In the worst case I'll keep using it with a USB keyboard. Thanks in advance!

Answer this question I have this problem too

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Only commenting that I have your exact same model with keyboard issues that keep either getting worse or completely get better with a reset of some sort.

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Most Helpful Answer

First disconnect the battery, then carefully slide the keyboard ribbon cable clamp to release the ribbon cable. Once you have the cable out inspect for damage either on the contact surfaces or the edge of the ribbon is torn. If you are sure the cable is OK, then re-insert making sure you have squarely entered the connector. You might find a piece of electricians tape folded over to make a handle mounted on the cable can help in pulling it into place.

Review Step26 in this guide: MacBook Pro 15" Retina Display Mid 2012 Upper Case Assembly Replacement

Give that a try and let us know what happens.

Update (07/03/2017)

Looking at your images the ribbon cable look OK and the logic board connector does as well. So the only thing I can think of is the pressure from the battery damaged the keyboard.

I don't think the isopropyl alcohol in its self could have damaged something here. Besides the mid frame wall would have contained most of the fluid as you worked on getting the battery out. Next time you should use ethanol alcohol as it does a much better job breaking the bond.

So now you'll need to decide if you want to take the easy way or the hard way... The easy way is just replace the uppercase. The hardware is taking the upper case out again and then remove the keyboard and just replace it.

Sorry ;-{

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Thanks for the response!

I removed the ribbon, checked for damage, and replaced it. I didn't see any damage; I linked a photo of the cable (https://goo.gl/photos/oQX8eu2L7bbRRRv3A).

The behavior is the same as originally described.

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Can you give us a nice picture of the connector on the logic board its self

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Re Hi will be eternally grateful.
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