Nixie tubes dying

[MattD]

Hi all, I'm new to this group so I hope it's ok to post this here.
I'm having trouble with my nixie clock slowly killing one of the IN-14 tubes. The full story is I bought a broken clock with the hopes of fixing it or salvaging the tubes. I couldn't fix it so I bought this clock board:

https://www.ebay.co.uk/itm/354407683845 (I think there are lots of identical ones from different Chinese sellers.)

It worked fine for about 3 months, then the 'minutes' digit started failing, starting with one of the numbers only showing the top half until eventually all digits had died. Thinking it might just be a tube at the end of it's lifespan, I swapped it for the one in the seconds position, and it ran fine for another few months so I was going to get a single replacement, but then one again the one in the minutes position starting failing in the same way. That indicates to me it's a problem with the board and that particular socket, rather than the tubes. I don't want to risk killing any more tubes, so is it worth just getting a new board? Or have I just got unlucky with the used tubes and they just happened to fail in the same way?

I tried testing the voltage it was outputting, and my multimeter seems to say ~194v for each pin, that seems quite a bit too high? But they all seem to be the same, so that wouldn't explain why it's only the one socket killing the tubes.

Does anyone have any ideas what to do, or if a new board is the only option, any recommendations for a good reliable and ideally cheap one, available in the UK?

Please let me know if you need any more info.

Many thanks

[gregebert]

This type of failure happens with leaky tubes. Carefully check around the base to make sure the glass isn't cracked and there are no bent pins. Is this tube location more-difficult to insert or remove than other locations ? Maybe the socket has an obstruction or bent receptacle ?

The next suspect is the anode resistor; if the value is too low it will cause excess current and the tube will wear-out sooner. If you swap tubes around, is this location always brighter than others ?

It's still possible you have not-so-good tubes. Many of the tubes circulating out there are used and you have no idea how many hours they have run. I dont have IN-14's in any of my clocks, but I have seen used 5031 and 6844 (Burroughs) tubes do this. Other people on this forum have had good experience with IN-14's. I've had great success with IN-18, and terrible issues with IN-1.