Procedure for setting high voltage

[DaveWM]

if the HV was higher than it should have been, then yes the brightness will be slightly lower if no other settings are changed (G2s).

I look for good regulation at correct voltage (generally about 23kv for typ 60's tube era 23v CRT).

I have found zeniths a bit more if a challenge with the pulse regulation vs shunt tube, but that may just be the varistor acting up. Doug H had a thread where he was running into this, think he was going to do some exp with MOVs vs NOS varistors.

when ever you are having problems with getting HV to work right I would suggest starting with new tubes (HO/REG/HV rec/Damper) before getting into any real diagnostics.