04-18-2016, 01:55 PM
I hooked up the heater wires to my BK 467 CRT tester so I could vary the heater voltage. I varied the voltage from 6.3 to 7.5vac and saw very little changed to the "negative" effect. The CRT did get just barely a very little bit brighter. I did not want to go any higher on the heater voltage seeing it seemed to make little difference.
Crist