ZX81+38 a clone of the ZX-81
| Project The main ZX81+38 page | |
|---|---|
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| This is a forwarding page to the now marked Completed main page. | |
| Status | In progress |
| Contact | mahjongg |
| Last Update | 2023-11-29 |
This project is completed, but the whole story about its design can be read here: https://revspace.nl/ZX81plus38_simple_to_build_ZX-81_clone
here you can see it working: 
I also wrote a document explaining how to build the ZX81+38 and test it if needed, you can read that here: https://revspace.nl/Buiding_up_and_testing_the_ZX81%2B38_revision_1,9
on 2 December 2022, I have ordered PCB's from PCBWay to built my own copy, using the keyboard PCB instead of my hand built keyboard.
You can get all the files to produce a ZX-81 clone here from my gitHub page: https://github.com/mahjongg2/ZX81plus38 (revision 1.9 is the latest version (in march 2023). there are files to produce the PCB's (both main PCB and a keyboard PCB that fits inside the plastic), as a replacement for the keyboard foil, but this keyboard has real mechanical buttons, you can use a plastified keyboard overlay and can choose to have short keys just under the paper, or you can punch holes in the overlay and use buttons with longer plunger that stick through the keys. This won't effect the legibility as all texts are organised around the punched holes.
Obviously the GitHub Page also contains the latest schematic (for revision 1.9) a placement diagram (drawing) and a Bill of materials that has data about where you can buy the exact parts (especially important for the connectors). you can choose buying the parts from Farnell (element 14) mouser or from Reichelt. Obviously you can choose any other source, but then use the order page of one of the given sources to check if you are buying a correct part. in the start of 2023 the total parts cost were something like $40, excluding PCB's).
if you want to spare some PCB costs, you could use a cheap single sided perfboard (AKA DOTBoard) with holes at 1/10 of an inch. The buttons will fit exact in the 1/10" pattern and it will still be possible to use the keyboard overlay, and hand wiring them is relatively easy.