The following step-by-step visual tutorial was prompted by a series of Facebook posts by Miguel Angel Rodríguez Jódar to whom I owe thanks!
Step 1: Ready to disassemble it. There are six screws that need to be taken off..
Step 2: With the cover removed the bottom side of the PCB is exposed
Step 3: Then, 8 screws more need to be removed (third bin in the picture) to separate both boards (main board and daughter board) from the case. Here you can see also the screws that hold both halves of the case together (Left and middle)
Step 4: Keyboard removal. (Don’t take the board yet). DELICATE OPERATION AHEAD: keyboard connection must be gently removed. Start with the smallest one, then the one close to it, and last, the one at the left of the picture.
Step 5: Keyboard removal. To remove each connector, grab it as close as possible from the socket and, gently, pull it vertically