Nixie clock, '6' digit doesn't work

Kits Timers and Clocks
1

Hi there,

I put together the Nixie Clock kit, and the problem that I’m having is that the ‘6’ digital across all the tubes doesn’t work. All other digits on all the tubes work, but the ‘6’ is uniformly out. So it doesn’t light when it displays “60” on start-up, or then it’s cycling through the digits as a test.

I swapped out the transistor corresponding to the ‘6’ digit with another one, and the problem persists. I checked for 5v at the base of the transistor and the output of the microcontroller, and it appears to be there.

Any troubleshooting advice? It’s not even that huge a problem, since the ‘6’ would not be used commonly, but I’d still like to get this sorted out.

2

Check for +5V pulses at pin 9 of the controller.
Check if +5DC pulses arrive at base of T15.
Check T15.
Check for bad connection between the two PCB’s.
Check for interrupted pads/tracks.