One of the 3-500z experienced with "flash over" problem recently. I am not sure if the tube already damaged or it can re-condition with burn-in procedure apply.
I plug in the tubes (both V1 and V2) into an empty chassis, with only heater voltage connected, no HV. I have observed the V2 (flash over tube) heater not light up correctly, compare with V1.
I have no idea why it is, need to check later.
