Category Archives: ZX81

Sinclair ZX81 related projects

ZX81 Ram Pack Issue 1 4164 Update

Posted on 1 June 2020 by levoman

Goal:- Replace 4116 chips with 4164 chips and make pack more reliable and eliminate the annoying ribbon cable. Please note that this will not give you more ram even though 4164’s are 64k the ram pack is only designed to … Continue reading →

Posted in ZX81 | 1 Comment

ZX81 Ram Pack Issue 3 4164 update

Posted on 1 June 2020 by levoman

Goal:- Replace 4116 chips with 4164 chips and make pack more reliable. Please note that this will not give you more ram even though 4164’s are 64k the ram pack is only designed to address 16k. Got a Rampack to … Continue reading →

Posted in ZX81 | 3 Comments

ZX81 Peripheral supply pcb

Posted on 1 June 2020 by levoman

Update : Now includes cad designed pcb The object of this project is to give the +5v and +9v supply to power ZX81 peripherals without a ZX81. For this project you will need :- Some Veroboard 10uf 16v capacitor 7805 … Continue reading →

Posted in ZX81 | Leave a comment