K8099 Nixie clock runs to fast

Hello Forum,

I did already assemble 5 clocks so far I am not a beginner so to say.

There is a strange problem with my latest one; It runs ahead of time!
At startup it detects the 50HZ net-frequency correctly but every our it runs about 5 minutes faster than realtime.

Any ideas?

Best regards,


Are you running it from an AC adapter plugged in the regular 230VAC 50Hz mains?
Did you check the pulses coming from the zero cross detect circuit? Maybe the mains or supply is too noisy, which can cause false spikes.