It may be because the power supply of the ICL7107 is unstable or the wiring is incorrect. It is recommended to check whether the power supply is within the specified range and check whether the wiring is correct. It is also possible that the ICL7107 chip itself is faulty and needs to be replaced. Careful investigation of these problems can solve the problem of digital tube light and extinguish.
Because the power was too high and the nixie burned out.