CRT Operating Hours until Ion Burn Appears

[andy]

...

[dreyfoos]

Hello Eckhard,

I found this on page 385 of Theory and Design of Television Receivers by Sid Deutsch (McGraw-Hill, 1951): "The ions cause chemical contamination of the screen phosphor after several hours of operation, to the extent that a visibly darkened center area is produced. This is known as the ion spot."

There are about four pages of discussion and diagrams.

Roger