We did a video a while ago showing the use of a key stem tester that was developed to make testing the Mutsumi key stems from Amiga, C128 and C64 keyboards. This makes the process of measuring the resistance more accurate, more repeatable, much quicker and easier. The project is open source but there was some interest in obtaining a PCB itself or a kit which includes the 3D printed housing.
The PCB is 1.6mm FR4 with a ENIG (gold) finish to help prevent the key contacts from oxidizing. Building the kit just requires soldering on two wires and installing four screws. The screws included with the kit are #4 but 3mm screws will work as well.
NOTE: The PCB is available separately or comes as part of the complete kit.
What is in the kit?
|PCB, 1.6mm FR4, ENIG (gold) plating
|3D Printed housing, PLA plastic
|#24AWG wire, 8" lengths