It took me a while to understand the key mechanism because it was different from the one shown in the first video I watched about this topic. Anyway, after several tests and with the help of my son Fernando (yes, he’s helping 👏), we figured it out.

NOTE TO SELF: If I had watched this other video, I would have understood it in minutes. But what’s the fun in that? 😄

How it works

  1. The small square (1) inside the key is actually made of two metal pieces sandwiched together.
  2. When a key is pressed, key holder (3) moves down and pushes the center of the metal piece that looks like a Y (2) against the center of the square (1). That’s what closes the circuit and registers the key press.
  3. There’s also a spring (not shown in the picture) that brings the key holder up again after the press.


In most cases, the solution is simply to bend the Y-shaped metal (2) piece back to its original shape. I think it gets flatter and flatter over time, and the key holder ends up not being able to press it with enough force agains the piece (1).