I recently bought an old Soviet era VFD clock, because I wanted to study how they built these things back in the days.
Unfortunately it wasn’t working when I got it so I took it on myself to fix it. Opening it up delivered a treasure trove of old tech; featuring at its very center a KP145IK1901 (Cyrillic: кр145ик1901) chip with a funny package, before even DIP became the norm.
It’s very hard to get information on this chip, but there’s an existing datasheet in Russian. It seems that it’s a micro-controller with VFD related peripherals built into it (e.g: high voltage output).
The fix was pretty easy; all I did was re-solder the transformer. It seems like a cold solder joint ended up killing the clock.
Moving on, I plan on building new projects with vacuum fluorescent displays; so stay tuned for more tutorials on this cool old tech!