Westinghouse K840CK15 Restoration

[etype2]

Originally Posted by Electronic M

P4 = monochrome phosphor, P1 =green oscilloscope phosphor, P22= tri color phosphor for color TV. Previous letter(s) is a randomly chosen identifier picked when the tube is registered as a new type with IIRC the RMA. There were other types of phosphor (for a variety of applications including radar) with their own P number (Wikipedia has a list). A 7JP4 tv CRT and a 7JP1 scope CRT are identical parts asside from phosphor color and you could interchange them with each other with out issue (as long as you don't mind a white scope trace and green TV picture).

GOOD TO KNOW. THANK YOU.

In 1968 the government passed a law that TV screens had to be sold and CRTs identified by viewable area diagonal and not envelope diagonal. Many tubes made after that point had a V as the first letter and the diagonal number was 2" smaller....So a 1966 25XP22 might become a 1969 23VXP22.

I LEARNED ABOUT THIS MANDATE BACK IN THE DAY. I TAKE YOUR POINT.

I don’t recall anyone discussing copper chassis? Benefits?

[trinescope]

About the only benefit to a copper plated chassis I can think of is it will be a better ground plane than plain steel, especially at RF. I really can't say how much of a difference it makes in reality since so many TVs were made with regular old steel and they worked fine.