04-15-2020, 02:26 PM
OK. You can find tube pinouts on line, or trace the heater wiring. Continuity checks are easy and will settle the heater condition quickly. For example:
50B5, pins 3&4 https://www.radiomuseum.org/tubes/tube_50b5.html
50B5, pins 3&4 https://www.radiomuseum.org/tubes/tube_50b5.html
I don't hold with furniture that talks.