and the ArduiNix shield (arduinix.com)
Those driver ICs
Just putting a bigger resistor in there isn't an option;
When talking about a product please provide a link so we know what it is.
Your problem seems to be with the hardware of a commercial product so it is your supplier who should answer the question.
In where and why is it not an option?
Where on that site is a schematic so we can tell what we are dealing with, as I said a link would be good.
Where are you getting this information about 70V being the minimum you can get from the driver, it is not what the 74141 gives.
Do you understand the fundamentals of neon lamps?
The 74141 is an open collector output with Zener protection diodes. When the outputs are OFF... no current flows through the TTL IC gate output transistor though the zener protection diode will happily work independently of gate status. When the TTL Gate is ON, it supplies a ground path to the NIXIE segment, closing the circuit and allowing it to light. A standard neon lamp operates at 60-80V, a Nixie operates at 170V. using the same ttl gate IC for the two devices is impractical.
I tried a 1M in parallel and the neon went so bright I