The Spectrum Clock
I wanted to build something using larger tubes. I chose the IN-18 tubes (originally made in The Ukraine by Gazotron) which have a digit height of around 40mm. Some ebay research resulted in a package being delivered from The Ukraine.
The Spectrum build is actually simpler than the QTC, resistor networks help reduce the component count and as the board is bigger, everything is a little more spread out.
The initial tube test confirmed that all is well, next up was the circuitry for the RGB LED’s (which illuminate the tubes if desired) and the various switches and sockets which are used to control the completed clock.
A useful addition is the optional PIR detector which will switch the clock on for a pre-determined period when activated. This means that the tubes are powered only when someone is there to look at them, thus preserving the life of these vintage items!
The finished clock now sits proudly in the family room and is admired by all – especially me!