Anyone built a ZX Spectrum Clone from scratch?

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Anyone built a ZX Spectrum Clone from scratch?

Postby Corneleous » Sat Oct 07, 2017 8:52 pm

I like the idea of a vintage computer, that was made completely with off-the-shelf components. I feel like a machine made this way is fully serviceable. Also, if you really wanted to, you could build one from scratch. The original Apple II's were this way, until the IIe (I think) started shipping with custom chips, which dropped the chip count for the motherboard from 120, to 31! At the time, it was probably great for consumers, as this surely made their product less expensive. However, if you have one today and that chip is bad, I'm not sure if you can find a replacement part easily.

For folks who grew up in the UK in the 1980s, their computer of choice was arguably a ZX Spectrum (much like lots of us here in the states had a C-64!) A guy named Chris Smith, who was also seemingly frustrated that the Spectrum combined several chips into a custom "ULA" chip, reverse engineered the ULA, and designed a PCboard that will fit in the original Spectrum casing, but uses no custom chips! He actually wrote a book about this process: ... m+ula+book

Some ZX Spectrum fans continued on the initiative started by Chris, and the result is called a "Harlequin Superfo." This replicates a ZX Spectrum 48K exactly. The board gerber files (these are the files needed to have a circuit board made at a board house) are available online, but also kits are for sale, ranging from just a pre-made board, to a full kit, much like we sell the PE6502 here. For more info, please check out this website:

Also, since Spectrums are sort of hard to get here in the USA (and even if you get one, it is hard to use, as the power supply is not readily something we can use with out 110 outlets, and also it is configured for PAL TV) what I find neat is that the Harlequin has an onboard option for PAL/NTSC, and can use a more standard power supply. Finally, you can order reproduction cases, keyboards (the ZX Spectrum 48k had a built-in rubber keyboard), and all other parts, so that you can make a functional replica from all-new parts. They even make them in alternative colors! See this website for the cases/faceplates/keyboards/keyboard membranes:! ... category=0

If anyone has built one of these, please tell us all about it, and post some pics!

Also, somewhat related, a computer we COULD get here in the states, the Timex Sinclair 1000 (I think this was called a ZX80 in the UK? or was it a ZX81?) has also been reproduced, by non-other than one of our favorite tinkerers, Grant Searle:

Grant's hardware projects website is just pure awesome anyways, and alot of you have told me you've built some of Grant's projects too. I think the Z80 based RC2014 project might even be based off of (or influenced by) Grant's "Simple Z80 Design".

Cool stuff!
Jason Putnam
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Joined: Sat Sep 30, 2017 4:53 pm
Location: East Coast, USA

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