History of the Spot-Killer circuit

[zenith2134]

I was curious: Which sets were the first with a spot killer? I bet pro video monitors had the circuitry before most consumer sets since their CRTs were higher-resolution and were therefore more expensive to replace if the phosphor burnt.

Always liked how a really old color set (or a later, cheap model b&w) will give that BRIGHT spot upon shutdown. I'm sure you guys know what I mean...

How about O-scopes and vector monitors? With no input signal, the phosphors are very susceptible to burning.