Zenith Advanced System 3 picture tube testing

[zeno]

You caught an awesome example of moire, best ive ever seen.
The Zenith folks described it as looking like a finger print
when we first encountered it on the old 14" tube jobs. We
had someone with a new 14" Zenith we sold bring one in for it.
After that it could be spotted in other sets even much older
ones.
One things for sure, all 3 guns have great emission. Like I
said these jugs did odd things when bad, you couldnt glance
at them & say "bad CRT" a lot of times. Sometimes it was like
someone was in back changing the grey scale slowly so
you couldnt do a set-up. Good one minute & bad the next but
not by much.
For the purity take a little magnet from a junker, put it on
the corner of the bell. Slide it in & out & rotate it for good
purity, works most the time.

73 Zeno