In this project we will build a Sinclair ZX80 Clone with 16KByte of RAM and a 16KByte EPROM with dual ZX80 and ZX81 ROM images which can be switched by selector links. We will use the ZX80 Minstrel PCB from Tynemouth Software for this project (www.tynemouthsoftware.co.uk).
Link for ordering PCB is below:
https://www.thefuturewas8bit.com/shop/tynemouth-products/minstrel-zx80.html
Below are links to download the full Schematic, PCB component reference layout, info sheet detailing part suppliers, parts list, ZX80 logos and a zip file with the dual ZX80/ZX81 ROM image:
http://www.scullcom.com/ZX80_Minstrel_schematic.pdf
http://www.scullcom.com/ZX80_Minstrel_PCB_ref.pdf
http://www.scullcom.com/ZX80_clone_info_sheet.pdf
http://www.scullcom.com/ZX80_clone_parts_list.pdf
http://www.scullcom.com/ZX80_logos.pdf
http://www.scullcom.com/Dual_ZX80_ZX81_ROM.zip
New keypads are available from www.rwapsoftware.co.uk
The PCB and overlays are also available from Tindie store (https://www.tindie.com/stores/tynemouthsw/), alongside kits and complete built units.