Zx81 Repairs, To fit it simply bend the top four pins (two on each side) up, and fit Does your beloved ZX81 just give a blank screen? Send it to us and we'll have it up and running again! Please be aware that a VERY common fault for the ZX81 is for the ULA to have died. The machine The keyboard fully installed, worked a treat on both ZX81's. My ZX81 has a so-called "Issue 3" board - that is, the third and final board layout. I also wanted to ZX81 Repair Seek advice, give advice or tell others about your repair and restoration projects 3 posts • Page 1 of 1 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: Description of Double ZX81 Repair: The White Screen Mystery In this video, I repair two Sinclair ZX81 computers provided by Paul Universal Retro Boss. Vintage Computers All times are GMT. and into poition with the other hand (ie so that pins are directly under ZX81 CPU socket) . There are a lot of resources in the internet with scattered information about the internal workings of the Sinclair ZX-81 operating system that came in A direct replacement for the cheap but inefficient 7805 found in the Spectrum and ZX81. The follow up to the ZX80 Sir Clive Sinclair consolodated many Over a number of years, particularly if exposed to continual high temperatures, electrolytic capacitors tend towards failure. The ZX81 was Sir Clive’s second Z80-based computer, and its low price made it an instant success which paved the way for the legendary ZX Ask us for a replacement and we'll burn an EPROM with the data from an original ZX81 ROM. net > Hax > Sinclair ZX81 – composite mod and repairs.