34 Madesigned a reasonably well working cassette input port.33 Mafirst attempt to get cassette port working.30 March 13, 2016, REV 3.0 the first non prototype version.29 March 8, 2016, video signal is okay now.2 Inspirational sources used for the design of the ZX81+35.It will be fully open sourced effort (but note that the original design of the ZX81 and its BASIC interpreter firmware is still owned by Amstrad, although they have announced that using it is fine, you can find ZX81 ROM images online)ДЄs for now comments and questions on the design can be made here (raspberry PI forum off topic section) :-) Some history about why I wanted to create a ZX81 clone can be found here: Note that due to the corona crisis (and the fact that I'm currently unemployed, so low of disposable cash) I have not yet build and tested the later ZX81+38 version, but as its based on the same schematic, I'm 99.9% sure it will work file. The ZX81+38 is now the preferred version, and is designed to be used as a drop-in replacement of the PCB of a real ZX81, with conventional DIP IC's replacing the ULA. So I also started on a much simpler to build ZX81+38, which can be mounted in an original ZX81 case, and is more a real clone, just with re-created ULA logic with discrete (PTH) logic chips. The ZX81+35 will be first built and tested in 2016.ДЄfterwards I got many comments that for a kit it was too difficult to build due to the use of SMT. My ZX81+35, ZX-81 clone, previously called the ZX14m ZX15, and ZX81+34 (2015 Version) retro homecomputer is a much improved Sinclair ZX81 clone built with the modern materials techniques and components of 2015.

Zx81 projects