Hi Group.
I have designed a PCB around Hans' Nixie multimeter design :
The PCB works just nicely, just been mounted on my newly aquired switch mode power supply, but i am having problems with the tubes.
I am using IN8-2 tubes, and have grounded the decimal point on the middle one to make the denoter of XX.X volts.
The problem i have - the transformer i selected for my power supply board for the tubes etc. is only putting out 165V DC after rectification, and that seems a bit low. The lighted cathodes in the tube steal the current from the decimal dot, so it goes out sometimes...
Any good ideas of what i can do ? A capacitor-diode doubler circuit seems a bit overkill, since i will be getting a voltage that is too high...
Maybe i need to redesign the power supply PCB layout ?
I have a proposed PCB layout here:
I have thought about two small PCB transformers, back to back to get around 230V to the tubes instead. I just had a bunch of these nice PCB transformers laying around from an Natural Gas furnace, with a 170V (unloaded) secondary and a 18V one too.
I know that putting a resistor on each cathode on the nixie would possibly solve the problem, but im not going to make new PCB's again (already on revision 2, since i swapped all connections on the nixies (0 to 9 etc :-O - dangerous stuff when you design two pcb's apart, haha)
TIA.
// Per.
