... returning to 80's computing
The first version of the NeoClassic modules
These modules are the functional equivalent to the five "RC2014 classic" modules.
I built the RC2014 Classic/Full Monty kit, but it didn't work after assembly. I spent weeks trying to figure out why it didn't work. I went over all solder joints, looked for bridges and bad connections. Tested the signal bus for continuity, but couldn't pinpoint what the problem was.
Since this was the most ambiguous soldering project I have done in my life, I can only blame my equipment and skills for this failure.
But I didn't give up. I thought that; if I made my own PCBs, I would have several attempts to make a working kit. So I started designing the PCBs, first in KiCAD and Eagle, but ended finishing the design in EasyEDA.
This is the first time in my life I designed PCBs. I must admit as a young man, I did sketch out a Z80 based computer. But at that time I didn't even know how to get the parts or make pcbs. It would probably not have worked anyway.
With the first version of the NeoClassic boards, I managed to get the kit to work. I made only a few errors with the first PCBs, but that was easily fixed with one patch on the CPU modules and 2 patches and 2 trace cuts on the serial board.
TIP: when making the first prototype, do not make a grounded copper area. With only copper traces on the board, it is easier to cut traces and patch lines when bug fixing.
With a working kit it was much easier to troubleshoot the failing classic modules, by replacing one at a time. In the end I found the problem to stay with the serial module, all the other were OK. With this knowledge I tried to overhaul the serial module, but it ended up completely fried.
After that I didn't see any reason to resuscitate the classic modules, they looked like a mess anyway.
The NeoClassic modules have undergone several revisions, but the changes are mostly estetical, but have also tried to make the design more intuitive and user friendly.