This guide is for models using hinge type K30. This hinge type is used in the following models:
Some colors in the pictures may differ for your model. That is fine, what matters most is the shape of the hinge piece.
The plastic hinge mechanism must be oriented as shown for it to fit onto the metal keyboard hooks.
Hook the top edge of the hinge over the top metal hooks on the base of the keyboard.
Snap the bottom of the hinge into place, by pressing down evenly on the bottom of the hinge. The bottom inner plastic hinge should snap into place under the wide metal hook on the base of the keyboard. You can now check that the hinge works by flexing it up and down; it should pivot easily at its axis.
If your keyboard is missing the rubber spring piece, place it in the center of the hinge. It will be held in place by the surrounding key and hinge.
Align the key on top of its place on the keyboard, and press down evenly. All four corners of the key should click into place.