X200 Keyboard - The curious case of the keyboard replacements

[mealex]

This is my first time posting to these forums, so please let me know if I should be posting somewhere else.

A while back I dropped my X200, lost a few keyboard keys in the process, and actually bent the metal platform of the keyboard. That means that even if I replace a couple of key on my keyboard, they won't fit into their original space any longer. However, it does still work fine. I just have to press on the blue plastic "cone" instead of a key.

I found a used x201 keyboard on Ebay, installed it on my x200, but it was a no go. First the X-V keys, a few number keys, and a few of they keys along the top failed. I shut it down to get into the BIOS, but then the power button started failing. I decided I would order another keyboard via ebay.

Found another one for sale, pulled from an X200, about 15 miles from my house and it was supposedly tested and working by the seller. When I received it a lot of keys all over the place did not work. However, running through the hardware check it seems like sometimes I simply needed to press a key several times for the machine to pick up on the key. All of the keys not working on the first replacement keyboard are not working on this keyboard + a few more.

The funny thing is this: The first replacement keyboard, pulled from the x201, started working pretty regularly. I've had it on my computer for a few days and all keys work except for the left 'ctrl' key, the 'screen brightness up' key, and the '5' & '6' keys. However, if I push down even the smallest bit on the top of the keyboard, just to the left of the power button, everything work perfectly. Under the keyboard, this is where the ribbon cable claps down into the keyboard, so I'm assuming it has to do with the connection between the keyboard and the ribbon. If I tighten that clamp, however, it does nothing.

At this point I have 3 keyboards.
#1. Has missing keys but types perfectly fine. I'm afraid of trying to bend this one back into place and accidentally damaging my only fully functioning keyboard.
#2. Pulled from an x201 and has a few keys not working. When pushing down on the top of the keyboard, everything works fine.
#3. Many keys not working, pushing down on the keyboard does do anything. All of the keys not working on #2 also don't work on #3.

I feel fine opening up a computer and swapping out parts, but have never tried to repair a piece of hardware like this. I don't even know what I should look for once I've detached a ribbon cable. Does anybody know what I should look for if I do open up keyboard #2? Why would pressing down on the keyboard make all these other keys work?

Do I even need to open up keyboard #2? Is it possible that I've damaged the keyboard connection on the motherboard since the same keys seem to be failing on two replacement keyboards? That doesn't seem to make sense since my original keyboard still works.

Any hints would be much appreciated!