keyboard mystery

[r3dplanet]

I have a very, very odd keyboard situation with my Thinkpad L412.

I run a computer repair outfit and this Thinkpad was handed over to me by a customer to recycle. But I thought it was too new for that. I upgraded the memory, processor, and hard drive. All good.

One huge problem: half of the keys don't work. Here are the keys that do work, the top and bottom rows:

1234567890-= [ but not the backspace key]
zxcvbnm,./

The keys that do not work are the middle two rows:

qwertyuiop[]\
asdfghjkl;'

Also, the caps lock and up and down arrow keys do not work.

So I replaced the keyboard with a new unit, and it exhibits exactly the same problem. Thinking that this keyboard might be off, I ordered another new unit with a slightly different FRU (45N2423) and it also has the exact same problem.

A month went by before I gave in and replaced the motherboard with the a new one that I found a great deal on. Guess what? It has the same problem.

Now I'm totally confused. I've confirmed that the keyboard replacements are US English keyboards.

Does anyone have any bright ideas? I'm all ears!

-marcus

[rkawakami]

In which application(s) are the keys not working? If you access BIOS does the up and down arrow keys work there?

[r3dplanet]

Exactly. From the BIOS these up/down arrow keys don't work, neither does caps lock, etc. When I pop in a live Linux Mint CD it's exactly the same. So it does really seem to be a hardware issue.

[r3dplanet]

It turns out that by removing the battery and the power supply and holding down the power button for thirty seconds managed to clear whatever bit was causing the trouble. All keys are go!

I hope this can help someone else in the future.

-marcus

[rkawakami]

Thanks for coming back to post your fix. That "power clearing" routine is said to work on other problems as well but it hasn't personally worked for me yet.