T550 keyboard frustration

[jruschme]

A while back, I picked up a "for parts" T550. Surprisingly, it all worked with the exception of the keyboard which would not respond to about half of the keys. Since the original keyboard was pretty nasty, I figured that might be the issue and purchased a new one. This seemed to work at first, but I started to notice some keys becoming intermittent and others not working at all. I tried a few things like using deOxit on the keyboard connector and taping down the latch, but nothing seemed to help.

Assuming that the issue might be with the motherboard, I picked up a used T550 motherboard. It arrived today and I immediately installed it... and it made no difference. Both the original and replacement keyboard have numerous dead keys (mostly the same ones, but a few more on the original keyboard).

At this point, I'm stumped. The only thing that I could think of would be something on the original motherboard is damaging something in the keyboard, but the only way to test that would be yet another keyboard and I'm loathe to sink another $20 into this without assurances. Unfortunately this is also my only 15" ThinkPad, so I have no other one to swap the keyboards that I have into.

Thoughts?
JR

[RealBlackStuff]

Have you checked the keyboard driver?
Do you have an external/USB keyboard?
If that also not works, you might have a Windows problem.
If you have an SSD or USB-stick or CD with Linux, try that with all keyboards.
If still no go, you most likely have a motherboard problem.
Liquid spill/junk/dust in the keyboard connectors?
What happens if you disconnect the trackpoint cable?

[jruschme]

Have you checked the keyboard driver?
Do you have an external/USB keyboard?
If that also not works, you might have a Windows problem.
If you have an SSD or USB-stick or CD with Linux, try that with all keyboards.
If still no go, you most likely have a motherboard problem.
Liquid spill/junk/dust in the keyboard connectors?
What happens if you disconnect the trackpoint cable?

The problem shows up at the BIOS level. Simple case: I can be in the BIOS settings and the Right Arrow will work while the Left won't, same for Up and Down.
External USB keyboard works fine.
Not running Windows on this one, just Fedora 42.
As I said in the original post, the problem happens with two different keyboards and two different motherboards in any combo of the two. It only seems to make sense of something in the original motherboard is damaging keyboards or something in the housing is causing issues (seems odd but possible, I suppose). That or totally bad luck.