Panaplex Clock - PCB
This is what the inside of the Panaplex clock looks like. The 180V power supply is on the lower right of the circuit board. The microcontroller timekeeping circuit is located underneath the leftmost digit.
The clock uses a regular 32KHz watch crystal to keep the time, but I left room for a DS3231 timekeeping chip. It supports a battery backup, and you can see the place where it would go on the board right underneath the hour digits.
Panaplex displays must be multiplexed to prevent damage. They are slightly more finicky than Nixie tubes, but the driving circuit is quite similar.
See tubetime.us/?p=16 for more.