Nixie K8099 reset controller?

I have already one clock running for serveral years with all tubes are lit 24 hrs.
Now I completed another clock and found default blankning In some of the zeroes.
Is it possible to reset the controller ?
Thanks for help

Thanks. In trying to faultfinding in a slow manner . I have built serveral professional electronics at work since 70 ths but of course i make my misstakes during the asembly or construction.Also build serveral nixies at home. I have tried to swap the tubes. But do not understand ”show this hour ” how I reset this function? NeXT step is to look at driver stages. But why do i have zeroes sometimes? And sometimes not. Can it be the controller?
I have larger tubes than supplied. I use GN4


Hello @sparky1

Like a zero don’t work (have you try to swap nixie tubes ?)
or the time format is ’ '1:00 instead of 01:00 ? or something else ?

Have you see page 10 and page 11 in