Just how bad can an Ion burn be?

[Electronic M]

Originally Posted by Tubejunke

LOL, we forgot to talk about the sets that left a single spot at dead center of the crt for a few minutes after the set was turned off. I have heard that those crts can show a burn, but I'm sure it would be after many years of service. And the only sets I've ever seen that do this are 60s sets which means that it has nothing to do with ion traps as they were gone the way of the Edsel by that point in time.

Point being I guess that not just ions can destroy the phosphor of a crt. Any type of concentration of the electron beam over a long duration will burn into the tube. That's why we turn down the brightness if working with a set that has lost vertical or horizontal deflection. I made the mistake of not doing that years ago and ended up with a perfectly performing set with a beautiful line burned into the crt.

I had an aluminized CRT in a 59' Zenith with the power-off spot burn hole in the phosphor...I found a better tube in the last year and dumped the working one with the spot off on someone.