Question Laptop keyboard issues

[JMB1911]

I recently disassembled my Lenovo T540p for "reasons" and now the down arrow on my keyboard is not working. It was working before the disassembly.

I've reseated both ribbon cables mutiple times but that still didn't fix it. Is there anything else I consider trying before writing the keyboard off as busted?

 

[C1]

Sometimes all it can be is piece of trash/debris under the plastic key that limits the key's travel.

Use a powerful vacuum cleaner to vacuum the keyboard out. If that still does not work try an air duster spray on the affected key.

Keyboard keys are removable and replaceable.

http://www.laptopkey.com/Guides.php/Lenovo/Thinkpad/T540P/L107

You could remove the affected key, clean the underside key area then verify that the keyboard circuitry functions. If so, then work from there.