| Made by | Gazotron factory, Rivne, Ukraine |
|---|---|
| Digit height | 18 mm |
| Read from | the side |
| Decimal points | two, left and right |
| Bulb | 19 mm across, 55 mm tall |
| Leads | 13 wires |
The IN-14 is the tube in most of the clocks I build. It is a Soviet Nixie tube: a glass envelope filled with neon, with ten wire cathodes shaped as the digits 0 to 9 stacked one behind the other. Put a voltage on one of them and the gas around it glows orange in the shape of that digit. Nothing is printed and nothing is simulated — the number is the glow. The IN-14 is read from the side; the digits are 18 mm tall, and there are two small decimal points, one each side.
Where the tubes come from
The IN-14s I use were made at the Gazotron factory in Rivne, Ukraine, the great majority of them in the 1980s, and they have never been used. The factory stopped making them long ago, so every one that exists is new old stock. Each tube is tested on a live board before it goes into a clock or into a box as a spare — only the ones that glow evenly are used.
How long one lasts
Soviet factories guaranteed tubes of this generation for thousands of hours — the IN-12's sheet puts it at 5,000 — which, lit day and night, is well under a year. In practice most last many years. Two things decide it: how many hours the tube actually spends lit, and whether every digit gets used.
That is why my clocks have a motion sensor — the tubes rest when the room is empty — and why the display can cycle through all the digits: the six-tube clocks do it every night on their own, and the four-tube clocks do it when that effect is switched on in the settings. The factory label makes the same point from the other side: after a long rest it recommends running each digit for a minute.
What a failing tube looks like
Two signs: the tube starts to glow blue instead of orange, or the digits stop lighting fully — part of a number stays dark.
How to change one
The tubes sit in sockets, not soldered to the board. Unplug the clock, lift the tube straight out, line the new one up with the socket and push it in. About a minute, no tools. Every four-tube IN-14 clock ships with one spare in the box, and the tubes are covered for twelve months: if one fails in that year, the replacement is free.
Buying a spare
Tested spare IN-14 tubes are in the shop. They fit every socketed Nixie Star IN-14 clock. They do not fit IN-12 or IN-18 clocks — the tube families are not interchangeable.
Clocks with IN-14 tubes: all IN-14 clocks.
Figures are from the original Soviet factory labels in the tube-tester.com datasheet archive.