Average lifetime of a CRT?

[zeno]

Sounds like the Zenith jug got changed. Zenith always used Zenith
tubes ( EIA 343 ) or Rauland tubes (EIA 1101). Zenith owned Rauland
since the early 50's. IIRC the only exception was the first 14" color
that used an RCA ( EIA 274 ). In later years B&W tubes were mostly
Clintons. Small colors ( 9") also used an outside tube.

The NAP sounds like an RCA tube ( EIA 274). If its a NAP / Sylvania
EIA is 312.

TV life is based on the CRT. It was said a good set & jug should go
8 yrs. Average life must have gone to 20 yrs from the mid 70's
on with RCA , Zenith and some Sylvania tubes.

Last thing is the "bad" early 90's Zenith tubes. Zenith did extend the
normal 2 yr warranty on them. Up to 5 yrs on high end sets. The
tube would be free or at reduced price depending on age & price
of the set new. The dealer was also asked to pitch in with reduced labor.
No big deal, by then a CRT could be changed & set up in 15 mn.
The ones that got screwed were Sears customers. They bought most
electronics & self insured them. If your jug went in 2 yrs & 1 day
you got NOTHING from Sears or Zenith.

73 Zeno
LFOD !