I'm using a PCB with some nixies on it.
They are driven by the KD155IC, which is a clone of the SN7441. I run them on 175V with a 10k Resistor, should give them a working voltage of 145V, 3mA.
But a strange effect happens when cycling through numbers:
- Some numbers don't even display properly, the just produce some red-glowing something in the tube
- Some numbers display, but with a small or large blue glow behind them
- The rest display properly
Not working: 1 With blues-glow: 0,3,4,8,9 Normal: 2,6,7
Here are some images to understand what I talk about:
What I tried so far
- Changed tubes to a set of "know-working" which run in another project for a long time No Effect
- Mounted the "not working" tubes into a "know-working" circuit WORK FINE!
- Changed several KD155 ICs No Change!
- Tested KD155 IC's on other circuit, WORK FINE!
- Changed power supply. No Change
Does anybody has an idea what could be the problem?