Keyboard key switch repair

[folly]

I could not find any info on this so I will share this information with you all.

This week I got myself an Acorn Electron.
Everything seemed to work except one key on the keyboard which was always on.
I viewed a video on how to do repairs on a key.
Without any good result I tried :
- wiggling for a minute
- firm presses
- use contact spray
- use a compressor the blow old contact spray or dirt out.
- a bath in alcohol, after de-soldering and de-clicking from the metal base (also used the compressor later)

With the firm presses and using contact spray is seemed to restore itself but trying a day later it had the same issue so I again.

So I decided to try and repair the switch.
The pins are screwed in and can be extracted by turning them anti-clockwise with pliers
The body is clicked and is therefor easy to open.
Be aware that there is a spring and 2 metal plates inside when opening so do it carefully.
I extracted all parts and cleaned the pins with tooth-paste to remove the oxide.
Then I cleaned all parts with a clean fabric.
The plates "pins" had to be bend a bit outwards.
This is the order to put it back in :
- white plastic
- the copper plate
- the silver colored plate
- the spring
- the cap
- the pins

When both plates are in place on the plastic very tiny pins then you have to see if there is no connection to the pin when inserted.
One hole is bigger to prevent connection so you have to see some black plastic when viewing in the hole of the plates.
If that is OK then you can put the cap back and you can insert the pins again.
Then you can measure with a multi-meter if the switch is good again.

This is how it works.
When pressing the white plastic down the 2 plate pins are pressed an will connect to the regular pin and the connection is made.

I hope it will be useful for somebody else.

Happy repairing without buying a new switch.