I would suggest you build an external spinner circuit first to check if your tube is 100% ok. Although these A-101 tubes are tough, there still might be a problem inside the tube; the discharge has to 'jump' from one electrode to the next.
With a spinner circuit you can check if the all dots are ok, and if the tube is ok.
I have a circuit diagram that you can connect to Ian's PCB where the A-101 is now soldered on. It is handwritten, but if you want I can make a decent circuit diagram for you and post it here. It uses junk resistors, cap's and diodes that you hopefully have somewhere available in a drawer.