Can't find any documentation about this on the web, and it's a PITA, so here goes.

Note: No pictures. I was too scared to take time out to take pictures.

Disassembly is not hard at first. Three screws hidden over the battery pack allow removing the cover over the power button and wireless switch, which then frees 4 tabs that lock the top of the keyboard down.

My keyboard was also taped down with double-sided tape, and glued down. This is the part I hate, both because I still haven't accepted that the common way to put together consumer electorinics is tape and glue, and because it's never possible to get it apart undamaged. I pried the keyboard up from the top, pushing under to untape/glue, and taking care of the cable. There was also a flap of plastic stuck down over the cable, which had to be peeled away. Many clips on the bottom of the keyboard hold it in place and have to be slipped out. I ended up slightly bending the arrow keys of the keyboard in yanking it out, though I think they'd still be ok-ish. Luckily I was putting in a new one.

Removing the keyboard cable was strange. Its socket is not the typical kind you can life to unlock. The socket is one piece and does not move at all. I eventually just pulled the cable out of it. This is where I started to get very nervous.

Replacing the cable was a PITA. You have to bend its end at a 90 degree angle, and then just line it up and press it down into the socket. Hard. And rub along it and do whatever you can to get enough force exerted down the thin cable strip to make it slip far enough into the socket to work.

I booted up the laptop several times while doing this, to test if I had managed to get it working. Eventually I had.

Then I very carefully reseated the keyboard, and replaced the cover and screws.

Unfortunatly, the tape and glue was doing something. The new keyboard is very springy in the middle, where that held it down before. So I will have to take it apart again and put on some new double-sided tape or something eventually.

Conclusions:

• Fujitsu sucks for not springing for an extra 0.01 cents for a locking cable socket.
• Laptop manufacturers in general suck for using tape and glue. (Or for building weaghty mehemoths that use better fastening systems.)
• When it's been disassembled, a lot of the magic of a laptop seeps out for me and never really comes back. Maybe next time I should not do my own repairs, just to preserve that heady comsumer magic of not knowing what's inside?
• I'm still using Caps Lock for Esc, so why did I even bother?!
• New keyboards feel strange.