After making the mod to the video O/P of my ZX81, as described here, I discovered that my TV would not successfully display a picture. This seems to be a common problem with non-CRT TVs so a solution was needed.

Just as I was thinking about doing a more intrusive mod I discovered the Minstrel ZX80 Clone project from Tynemouth Software. I ordered the PCB and it arrived the next day.

The PCB came complete with a comprehensive list of components together with suggested sources for the rarer ones. Strangely it didn’t come with a circuit diagram, which it should have done considering Tynemouth have modified the circuit.

This isn't really building a computer so much as it is assembling a computer. In this DIY Hacking series, we will actually build a computer based around the Z80 CPU. In the process, we'll learn how it works and how to program it! Disconnect the USB-serial adpter from the PC, and add to the Z80-MBC2 the SD module (with the microSD inside) and the RTC module (if you have it). Pay attention to install the modules exactly as shown in the photo, because they aren't 'swappable' in their positions, and permanent damages may occur if you exchange them! After successfully building a Harlequin 128K, and chatting online to @6502Nerd, who has built his own homebrew computer based upon the 6502, I decided to have a crack at it. The aim of this project is to build a fully functioning Z80 based computer. RC2014 is a simple 8 bit Z80 based modular computer originally built to run Microsoft BASIC. It is inspired by the home built computers of the late 70s and computer revolution of the early 80s. It is not a clone of anything specific, but there are suggestions of the ZX81, UK101, S100, Superboard II and Apple I in here. First Efex computer designed in 1998 by myself and dedicated to my son Efe, initial version was 4Mhz, 4 kb memory and simple out of standard serial comunication protocols. This winter I decided to re-design and improve this Project and let other hobbiests can build their own z-80 computers.

I have been through my component boxes and have a number of the required components already.

Although the Minstrel ZX80 Clone project is based on the ZX80 it is designed to fit into a ZX81 case. Fortunately I have a ZX81 I can use; I also have a ZX80 with an original ZX81 upgrade ROM I can install into the Minstrel PCB.

Z80 Computer Kit

Next task is to order the missing components. Once the machine is working I will use it to test the diode PROM and basic LED output circuit.