Introduction

When it comes to hobby projects, clocks have always been one of my favorites. I've made them with LEDs, planar neon displays, monodigichrons, some with microprocessors, FPGAs, TTL logic, etc, but this time I wanted to make a dekatron and nixie tube clock with a minimum of solid state components, except for maybe a few germanium diodes. As I thought through the design, the cold war theme developed along with some specific goals I had for the project:

   No semiconductor devices at all, only tubes
   Research every part, and use only components and technologies available in 1959
   Authentic military/commercial reproduction, not a unique or artsy style
   Reasonable size, less than approximately 1 cu ft
   Use a mix of Soviet and US components in key parts of the circuit
   Audible alarm
   Low power consumption for tube equipment, less than 60W
   Selectable 60 cps or crystal reference with decent accuracy
   Use original old parts wherever possible
   Learn about how products of that era were designed and manufactured

I chose the design year to be 1959 mainly because I wanted to use Sprague orange drop capacitors, and they were not introduced until that year. I like orange drops because they're more compact and reliable than wax and paper caps, can still be found in old stock, and I like how they look. Also, 1959 was good because the cold war was going strong then, and I had some parts donor gear from that era.

Design, build, initial testing, and documentation took about a year and a half. It was a balancing act of compromises to meet all the goals, but I'm satisfied with the results.

<<< saga continues at link above with exquisite detail on how the construction was done -- IT'S A MUST READ  >>>

A cost estimate puts this clock at $2130 in 1959, which equates to $17040 today. Clearly this would be outside the price range of most hobbyists. The actual build cost [Hank] around $1600.

Quoted:
I love those whirling Decatrons. They're fascinating to watch, especially after a few beers. There's one somewhere among my junk boxes.

They rank right up there with a teletype machine with the cover removed.

Quoted:
I love those whirling Decatrons. They're fascinating to watch, especially after a few beers. There's one somewhere among my junk boxes.

They rank right up there with a teletype machine with the cover removed.

Quoted:
I love those whirling Decatrons. They're fascinating to watch, especially after a few beers. There's one somewhere among my junk boxes.

They rank right up there with a teletype machine with the cover removed.

Quoted:
As long as we're going retro, how about a dial telephone exchange?