Just how bad can an Ion burn be?

[benman94]

Ion burn is just a consequence of not having an ion trap or an aluminum backed screen. The ions are too heavy to be deflected along with the electrons, so you get a big nasty spot on any trap-less, non-aluminized magnetically deflected CRT. All 12JP4, 15AP4, 20BP4, 12AP4, and 9AP4s will burn sooner or later.