This ZX81 was my original from back in 1981. One of my best friends at school, Mark Gravestock, had asked for a ZX81 for his birthday, and it’d been put away for the big day. He’d sneaked it out of the box a couple of times to play around with whilst I was around. And it was the sheer novelty of it that piqued my interest.

I don’t know what Mark is doing now, but he was a bit of a whizz kid at the time. I remember him writing a Z80 monitor in Z80.

I had to have one – so mithered my parents until they relented. We were not a well off family, and £69.95 was a lot of money for a gift, so my nan chipped in. I got mine a few months later in the summer of 1981.

I started off coding in BASIC, using the excellent Sinclair BASIC manual, but quickly tired of it. I tried to learn Z80 assembler by borrowing the book ‘Mastering Machine Code on your ZX81 or ZX80’ by Toni Baker. I had this book on more or less permanent loan from the local library. But it didn’t stick. It wasn’t until I got my Sinclair Spectrum a year or two later that I really got into assembler.

As well as typing in games listings from magazines, I enjoyed playing the contemporary games of the day including 3D Monster Maze and Mazogs, which is still in my top 10 favourite games.

My ZX81 has had a tough life. I loaned it to Tim Follin for a while, and it came back with cosmetic damage to the keyboard – a nick in the membrane. Tim apologised and said that he’d probably dropped something sharp on it. There was also an issue with some keys not working – the ribbon connectors had perished. So it’s been gently restored with a new membrane keyboard and the obligatory composite video modification.

It now has a new lease of life with a ZXPand+ replacing my original Memotech 16K Ram Pack. Not only do I have 32K of RAM to play around with now, I’ve also got SD card storage, an AY chip, and a joystick/serial port to play about with.

I’ve also purchased a copy of “Mastering Machine Code on your ZX81 or ZX80” and may have a crack at going through the examples in that, now I can quickly load and save the assembler and my source code to SD card.

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