Posted on Feb 5, 2014

I designed the ZX97 as a discrete copy of the ZX81, which was the first PC for millions of people. In the process ZX97 turned into much more than a mere copy. While it is backward compatible with the ZX81, it is in all other respects a significant improvement over the ZX81. In 1998, Rodney Knaap contacted me to offer to make a PCB of the ZX97 but

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this proved no small feat. The end result required 3 PCBs connected together with flat cables. In order to simplify the PCB for others to build I designed the ZX97Lite, a trimmed version of the ZX97 omitting the big RAMdIsk and the 8255 parallel port. For a full background on this story and details of Rodney`s ZX projects, check out Rodney Knaap`s Website where you will also find my original ZX97 article and schematic. Rodney has designed a single sided PCB for the ZX97L and also build and tested a prototype using this circuit. I have been unable to contact Rodney for a long time but I would urge you to try and contact Rodney for the latest CAD version of the ZX97Lite PCB. If you cannot get in touch with him, here are the beta version of the ZX97Lite single sided PCB ( ZX97LPCB - for 600pdi printer ), the ZX97Lite parts and jumper layout ( ZX97Lite Layout ) and my ZX97 EPROM file (ZX97L 27C256 EPROM binary image) While Rodney`s ZX97Lite schematic was a great improvement over my original ZX97 ASCII drawing, it is somewhat difficult to read because of the foreground and background colors, the dense layout, the bused signal lines, the IEC logic symbols, crowded pin numbers and in addition, it contains some minor errors and omissions In order to make the ZX97L easier to understand, I have redrawn the schematic by replacing the IEC logic with ANSI symbols, reformatted the drawing to black on white, renumbered pins and completed...

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