09 September 2020

Western Electric 6167 Dekatron

I am always alert on vintage display technologies and the latest common thread has started in mid-July 2020 at the first ham/electronics flea market after COVID-19 lockdown.

In Tortona open-air fair I found a Philips DG7-32 cathodic ray tube probably NOS and an 0D3 gas-filled cold-cathode tube. Having a CRT calls for a CRT clock, so I looked around for circuits and other CRTs for you-never-know-what-when. A small stock of National 2BP1 was on sale almost locally and the same guy had recovered a shoebox of NIB vacuum tubes (more on another post).

I poked around the unknown-to-me part numbers and gave them a meaning with the help of the smartphone. Amongst others, I took home a mysterious Western Electric 6167 Dekatron new in box, packed way back in 1958. The picture shows the original packaging, with a now sticky wax(?)+net foil and lots of soft paper. 

A dekatron is a counting device, or divider if you prefer. It is gas filled like a Nixie and some of them display a dot on the current count position. A datasheet is available, but no reference to original applications and circuits. Fortunately someone has already built a spinner with W.E 6167 so it was a matter of replicating the circuit.

Since everyone's junk box and equipment is different, I kept voltages from threeneurons's spinner circuit as a reference and generated them with two power supplies in series: 280V + 170V (make sure the second PSU is floating with respect to earth!). In order to get about 225V I used a sequence of zener diodes, which also provides a comfortable tap at about 60V. Finally, lacking a socket I used pins freed from a DB25 female to interface with the dekatron without stressing the pin-glass seal.

So, thanks to Mike "threeneurons" open work, this baby started spinning right away:

I like its un-usefulness  :)