Category Archives: ZX81

Fixing a poorly ZX81

L Break Into Program

You may have already read my posts on fixing my poorly ZX Spectrum, which ended up being possibly one of the longest retro repair projects in history. I also had a poorly ZX81. This was my first computer, and bought by my nan. It was this very machine that sparked my interest in computers that remains to this day. As far as I was aware, this machine worked, but was suffering from a broken keyboard …

Composite Video Modification for the ZX81

L Break Into Program

A few years back I attempted this mod on a Spectrum, based upon an old magazine article I’d stumbled across on the Internet. A link to my mod (with links to the original article) can be found here. The ZX81 video circuitry is driven directly by the ULA and, like the Spectrum, that signal is fed into a UHF modulator which converts the composite signal into an RF signal that a TV can tune into. …