Thanks to all your answers.
I do have the service manual for the Tyros 5, and I have also a Youtube that explains how to do it with the Tyros 4 but this person does not take the key board out, he just removes the keys just by taken the keyboard top off
and removing the keys holder in the back of the keys. It looks so easy, but the repair manual tells you to remove a lot of other things that maybe are not necessary to remove.
Thanks for the repair manuals page, now I can see that the Tyros 5 is exactly the same thing as on the Tyros 5.
Then is ok to follow the instructions that the Youtube movie shows, here is the movie:
https://www.youtube.com/watch?v=3sQWuB2XAcs Very clear instructions to follow.
Some how my nail is digging into a C key, I ordered from Yamaha, does not cost to much.
Thanyou guys