Czech Didaktik Alfa, Tesla PMD 85 and other computers

I found this interesting Czech educational computer. There’s an entry on wiki but most links are defunct and there are some new. First a pic with screen

Very interesting seems the yellow one, a PMI-80

Here are many photos with open case (Alfa)
The keyboard has Tesla Hall effect sensors, many details here
Hall effect keyboards –

Better info on sr wiki (with links and emulator, note that there are 2 articles, best is this)
PMI-80 – Wikipédia

(PMI 80 - Clous)
Ako som si staval PMI-80 | SinDiKat


Just a small fix, Didaktik (the company behind the Didaktik Alfa) was based in Slovakia, in the town of Skalica (Czechoslovakia was actually a federation since 1968). It was a clone of the PMD-85. Later also Didaktik Beta was produced, enhancind the Alfa.

PMD-85 was an i8080 based computer that took an inspiration from the HP-85 (but it was not a clone), that is why the 85 in it’s name. The reason for 8080 was that it was produced in Czechoslovakia (as MHB8080), Z80 was produced in the East Germany (as UB880D). Because the state of semiconductor production in the eastern block was… well, crap, the design was using many bad chips as it was plenty of them being produced.

PMD-85’s (there were about 5 modifications) were heavily used in education (my own first computer course that I attended at the end of 80’s was also fully done using PMD-85 computers) and were not really available for the general public to buy. Now there is a small but active community still producing software and hardware for the computer ( all in Slovak language).

The computer was created in Tesla Piešťany (famous bath city at the west of Slovakia), but soon it has moved to Tesla Bratislava (the capital of Slovakia) for better production capacity.

Software wise, it was using Microsoft BASIC (which was re-writen inhouse especially for the project), later also CP/M as disk drives were available.

Didaktik company (originally a supplier of educational stuff like rulers and so on) went on to manufacture ZX Spectrum clones in 1987 called Didaktik Gama. They actually survived all those times and closed just few years back, in 2020 (but the computer department was gone since about 1994).