Last but not least, the CPU Board that holds the MC14500 ICU, together with a 8-Bit Input and 8-Bit Output IC. Instead of the MC14599 Input / Output chip, I use the MC14099BCP instead - or it's still available equivalent, the CD4099B, that is still sold and available on DigiKey.

With all boards organized and planned, there is nothing to start the production of them and ordering the components.