Jeff_Birt
New member
I was doing some research earlier this year to try and find a way to rejuvenate the conductive rubber on the Mitsumi key stems used in the Amiga/C128 and also the C64. I needed an accurate and repeatable way to test the resistance of the rubber contacts. To that end I came up with a very simple PCB and 3D printed housing that works very well. I now find I use it when cleaning keyboards so I can test the stems before reinstalling them, that way I know the KB will most likely work properly when put back together.
It has one aperture that fits the Amiga/C128 stems and another that fits the C64 stems. This is for the Mitsumi keyboards only.
In case you are curious it is very easy to rejuvenate the conductive rubber, using common household chemicals, and reduce its resistance back down to a level that will work. I did a video about the process and will put the link below.
It is an open source project, link below. I had a batch of PCBs made up and an selling them as well as a complete kit in case you don't have a 3D printer. The PCBs have a ENIG (gold) finish to provide a stable contact surface for measurements.
PCB $1.75
Complete Kit $6.75
International Shipping ~$5.20, depends on PCB or kit
US Shipping ~$2.50, depends on PCB or kit
Easiest way to order is through my website: https://www.soigeneris.com/mitsumi-k...ter-pcb-or-kit
Github page: https://github.com/Jeff-Birt/C64_C12...umi_Key_Tester
Video about tester: https://youtu.be/n9gGz2n-sBU
BTW, sorry to have posted this in two separate places but it is applicable to the C64 and Amiga.
It has one aperture that fits the Amiga/C128 stems and another that fits the C64 stems. This is for the Mitsumi keyboards only.
In case you are curious it is very easy to rejuvenate the conductive rubber, using common household chemicals, and reduce its resistance back down to a level that will work. I did a video about the process and will put the link below.
It is an open source project, link below. I had a batch of PCBs made up and an selling them as well as a complete kit in case you don't have a 3D printer. The PCBs have a ENIG (gold) finish to provide a stable contact surface for measurements.
PCB $1.75
Complete Kit $6.75
International Shipping ~$5.20, depends on PCB or kit
US Shipping ~$2.50, depends on PCB or kit
Easiest way to order is through my website: https://www.soigeneris.com/mitsumi-k...ter-pcb-or-kit
Github page: https://github.com/Jeff-Birt/C64_C12...umi_Key_Tester
Video about tester: https://youtu.be/n9gGz2n-sBU
BTW, sorry to have posted this in two separate places but it is applicable to the C64 and Amiga.