This Nixie tube tester has an 11 position switch to change the displayed digits.
A simple device for testing and/or healing Nixie tubes of IN-18 type. An 11-pole switch is connected in series with a 50 KΩ pot (+ 470 Ω resistor for safety), powering from an 180V DC source. Normal operation at 2 mA is shown. For healing tubes, one can double the current (4 mA), baking the tube for several hours in order to remove cathode poisoning. Enjoy !