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TrashyMG

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Long story short I found my first computer in my Parent's attic when helping cleaning a little while ago or well most of it...

It's a Timex Sinclair TS1000 or a ZX81 known everywhere outside North America. I found it in a bunch of parts, sans case and keyboard, wasn't even sure what it was at first until I looked closer. Not sure what happened to the original casing, but all I can say I was a pretty destructive kid, always taking apart everything when I was young. Honestly these computers are so cheap I could get another working one for 24 US dollars off ebay, but I just felt the need to bring the thing back to life, this was literally the computer that sparked my interest in computers and electronics back when I was a young kid, I wasn't old enough to appreciate it fully. This isn't a restoration, but putting it back into a working order and doing some improvements along the way.

I took it home, hitched it up and powered it on and sure enough I could see the BASIC command prompt on the TV. not bad as it likely hasn't been turned on in around 35 years.

Next step was I replaced the inefficient 7805 with a modern switching regulator, this allowed me to shed the huge aluminium heat sink, which will allow the board to fit into a smaller 3D printed casing I'm still working on. I also put some heat sinks on the ULA chip as it gets pretty warm. As the computer only had RF, I found some pre-made solution that allows proper composite output off of some retro computer site I found.

Then there was the issue of the keyboard it was missing all together, finding a replacement is fairly easy, but the ZX81 and the ts1000 keyboards were those horrendous flat membrane keyboard, so I decided to make my own. Using a bit of Openscad and finishing it Tinkercad I was able to design a simple keyboard plate that allowed MX Cherry key switched to be used, which luckily I have a ton laying around thanks to another unfinished project. I replace the keyboard flex ribbon cable sockets on the motherboard with standard .1 pitch headers which was a lot easier to deal with.

I still need to design the rest of the casing, but it's functionally working now. it may end up being a bit thicker than the original system, but it will have a lot better keyboard.


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levi

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Nice, you're missing the BASIC keywords on those keycaps those though as well as the block characters. I don't like using these systems for BASIC coding on modern emulators since I can't look at the keyboard and work out what to press to get INPUT or PRINT to appear. Perhaps your muscle memory was better trained back in the day and has persisted better than mine has though.
 

TrashyMG

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Nice, you're missing the BASIC keywords on those keycaps those though as well as the block characters. I don't like using these systems for BASIC coding on modern emulators since I can't look at the keyboard and work out what to press to get INPUT or PRINT to appear. Perhaps your muscle memory was better trained back in the day and has persisted better than mine has though.
Right now I have a cheat sheet, I plan on trying to get some key cap labels printed out somehow....
 

TrashyMG

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Some of my sources for the modifications I've done. I'll likely attempt the 16k modification too in the future.

Also found some stickers for the keycaps, the page says Spectrum, but if you look at the actual product it includes keycap stickers for the ZX80,ZX81 and Spectrum.
 
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TrashyMG

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Have completed the 16k memory upgrade, playing a 16k version of 3d Skeleton Maze. Also the keycap stickers came in, a bit more glossy than I'd like, but may be able to do something about that. Going to complete the casing in the next few days and call this project closed.

I'll likely go back and make those patch leads on the SRAM a little more clean, I just wanted to see it work.

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TrashyMG

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Just about finished this, wanted a more elaborate design, but after a bit of frustration just went with a plain box design and will use some rubber feet or 3D printed legs to give it a bit of an angle. I decided not to expose the expansion slot, I have the 16k expansion done on board and won't need an external memory pack. I've added a switch to change the composite output from the normal white with black lettering to inverted black background with white lettering. Only changes I had to make was switch the keyboard .1 pitch headers to right angle ones as the cables sit too high to close the case. To hold the ZX81 board in I used rivnuts, but didn't actually rivet them in the plastic as that would likely break the plastic. I drilled the holes slightly smaller than the rivnut and pushed them through, then applied some glue on both sides to keep it in place.

It's not perfect, but it will do.

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