Make sure that all the power supply rails are present and within spec ripple-wise before going too far down a rabbit hole troubleshooting the nixies and their drivers. If the power supplies are too far out of whack, you'll never get it working.
That being said, the tubes are socketed, and can be swapped around between the decade/driver boards for fault isolation. If the fault follows the tube, it's likely the tube; if not it's in the driver. I believe that the lowest order decade counter (the one on the extreme right, least significant digit) is slightly different than the others as it must operate at a higher frequency than all the rest, but am not 100% certain if this applies to your counter; I seem to recall reading it with regard to the 5245L. Other than that, the remaining decade counter/drivers should be interchangeable with one another.
But to reiterate, start with the power supply section.
-Pat
The far right one has a different board it appears,
Thanks, I will start with the power, any good guides on troubleshooting ripple?
Im also measuring ~4volts from the case's metal at ~0.05 amps, is that normal?
If you remove the cards, the tubes may easily be swapped from card to card as they are socketed. The photo below shows a card from a 3440A DVM; the construction is very similar to those in the 524xL nixie counters. The large rectangular black plastic part that the tube plugs into is the decoder section others mentioned earlier in this thread. It contains the neon lamps and photo sensors used to drive the nixie tube. The tube is plugged into a socket on the front face; it may be removed by rocking it back and forth slightly whilst pulling forward on it.
As far as troubleshooting, what test gear do you have? A scope? That can be very helpful for looking at supply ripple.
I normally use an AC coupled scope probe across the supply rails to look at ripple. Take note that in this older HP stuff, there are often positive grounded supplies (meaning that the positive side is connected to chassis ground and the rail is negative). Be sure of how things are connected and don't just clip a scope ground lead to the negative end of the supply - you might wind up shorting it to ground through the scope and chassis ground if it's a negative supply. Best to get a schematic in hand before troubleshooting to see what's what.
How are you taking the measurement of voltage and current at the case? What sort of meter, and how is it connected? Is the mains cable well grounded?
If there's a lot of noise on the supply rails causing the decade counters to run at high speed, it can potentially make the tubes look bad as it will appear that multiple numerals are lit. I believe that pressing and holding the reset sends a signal that forces all of them to zero and makes them ignore any other input.
-Pat