Remaking the 78up5 2650 mini-computer

Many Australians growing up in the 1970’s and early 80’s had their first exposure to hobbyist computers through projects published inĀ Electronics Australia and Electronics Today International magazines . My first computer was the 2650 minicomputer published in May 1978 which was designated the 78up5.

Inspired by the creation of the Super-80 reproduction, another great Australian computer from the same era, I have created the 18up5 to bring this classic and simple design back to life using KiCad.

The 18up5 has the same layout as the original, and adds the option for a 2716 EPROM instead of the now difficult to obtain PIPBUG mask ROM. It also includes the option for a crystal oscillator instead of the monostable oscillator.

PIPBUG is running at 300 baud on the new board and I’m working on 4800 baud. The power-on reset is not working either but the manual reset works fine.

I’ll publish all of the circuits and schematics once it is fully operative.