ZX81 Technical Section

ZX81 Board Information

Schematics, Component layouts and port/connector pin-outs

Title Description Date
ZX81 Board Schematics The schematic diagram of the ZX81 -
Complete Parts A view of all the component parts that make up the ZX81 -
Replacing the ZX81's ULA Some background information on the ULA and links to some sites that have replaced it with discrete components 13th January 2015


ZX81 Firmware

Disassembly of ROM code and other firmware-related articles.

Title Description Date
ROM Disassembly The complete ZX81 ROM disassembly -
Z80 Instruction Set The complete Z80 Assembler list of instructions -
Assembly Language resources for the ZX81 A resource list for those interested in programming Assembler for the ZX81 -


Original documents written by third-party manufacturers of Sinclair peripherals.

Title Description Date
Sinclair 16K RAM Pack Board Schematics The technical schematic diagram of the Sinclair 16K RAM Pack -