CRT TV Question

[zeno]

Ditto Mr Squirrels
Classic symptoms of weak CRT. Wickid easy to change if
you wanted to.

Zeno

[Alex KL-1]

I have almost the same question...

But is a doubt, also... since I worked at a time with only in-line CRT, I dunno if have differences to a delta-gun tube: I have one delta-gun in collection (that one I yet have to correct some purity issue), but it have excellent image only after 2 or 3 minutes; it starts blurry. And, it have a maximum contrast it can show: If I try to crank it to have a more luminous image, it blurs a lot.
To be fair, it's brightness is good for night watching...

About this contrast limit, is that manner in delta tubes, or mine is showing it's age?

I like this CRT, it render the colors very rich; outstanding!

Another doubt (a curiosity/musing) now, if people don't mind: all delta-gun CRT are absent of the black matrix, or some use it? This CRT have very low light leakage between adjacent "pixels", like modern good CRT. The focused image is second to none... (after it warms)
Or, in another words, if the black matrix concept are apllied only to in-line CRT?

[zeno]

Black matrix delta tubes were invented by Zenith & came out @1968.
They were called Chromacolor. They started on high end consoles.
14", 16", 19" 23", & 25" were built. Improved with smaller dots,
more HV, flatter & more square tube over the years.
@1976 Zenith came out with another new tube. The EFL " Extended Field Lens"
or Tri Focus. Deltas got phased out over the next few yrs. EFL came
in 13", 17", 19", 23" & 25" The EFL was an in line gun & phased out @1981

Zeno

[Alex KL-1]

Interesting! Thanks, Zeno.