How can I diagnose a keyboard issue?
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.
- 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.
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!
Is this a good question?