One of my (if not the) 1st computers was Elektor’s (Elektuur in Dutch) Junior Computer.
I did buy it as a kit from a company called Musicprint, as they offered the cheapest version. Later on it became clear why their price was so competitive as they delivered some alternative switches , not the (more expensive) “Digitasten”, no crystal etc. Unfortunately these switches caused some contact bounce which was quite irritating when entering programs.
In 2018 I found back my original Junior Computer, but instead of restoring this I decided to strip it and design a new PCB, as close as possible to the original design , with the original “Digitasten”, even though they start to become hard to obtain.
How does this Single Board Computer look like :
Let’s start with some original documentation (you can find more on this site under the section “Bookshelf”).