B&K 1077B questions

[govee]

I am not sure what kind of lesson I just learned as in most of my limited radio work tubes are rarely without obvious damage bad enough to make a radio dead. Not work well, sure. My inexperience probably let me call what I was seeing as closer to dead than I should have. I decided to check the tubes in the video side just to be able to answer the question of had I checked the tubes and V13 was completely dead. Filament good, no shorts, but zero emission on either triode (is triode correct?). I subed in a different 12at7 and the 1077B lives again. I added a picture with replacement 12at7.

Andy