My computer history

3. 1982 I progressed to the ZX Spectrum which was 99, because I couldnt afford the BBC computer which was 399 in 1982!!!

I created Spectrum 3000, marketed by DK'tronics and made about 200. (Previously made for the Sinclair ZX81)

I had a lot to do with the ZX spectrum which involved the OPUS discovery disk drive system, which was brilliant!

user guide is here

OPUS dissembly of the ROM (text file format)

The Circuit Diagram is below

The Opus disk drive, designed for the Spectrum

OPUS circiut diagram , not drawn by me

Gif file, not drawn by me