Is amazing how some sets can function with half dead or nearly dead tubes! Like that Telerad oddball set that I'm still working on, virtually all of the 6SA7's had little or no emisson but the TV still seemed to work! Weird huh?
BTW I was rather impressed at those upclose shots of that CRT, such a sharp image and good definition too, not bad for a weak picture tube, I can only imagine what a good CRT will perform like...
Cheers Glen