What was the purpose of.....

[nasadowsk]

RCA said 15kv absolute was the point where it became an issue. AFAIK, most B&W TVsa were below that point...

[jr_tech]

Originally Posted by nasadowsk

RCA said 15kv absolute was the point where it became an issue. AFAIK, most B&W TVsa were below that point...

I may be remembering wrong, but I think that was the threshold voltage above which the BRH (later CDRH) required measurements/sample monitoring of production CRTs.

jr

[cbenham]

Originally Posted by N2IXK

My understanding is that X-rays are actually created from about 10 kV on up, but that below 20 kV or so, they are too weak to penetrate the glass tube envelope, so there is no way they can pose an exposure hazard at all.

I remember reading about the X-Ray Warnings for TVs in the '50s and I also remember an article in ??Radio and TV News?? stating that to receive the equivalent of just *one* chest X-Ray, a person would have to lie on the floor with an operating 21 inch set on his chest for at least 10 months. It may have been Radio-Electronics Magazine too.

I also remember reading about the gross overhype of wraping HV rectifiers
with leaded glass or a rubberized lead shield.

As for color CRTs with a shadow mask or an aperture grill, these reduce the major portion of any soft X-Rays coming from such tubes.

The only tube I know of that actually could be dangerous if you sat watching within 3 feet of it for days on end was the DuMont Royal Sovereign's 30BP4 CRT. And if DuMont had aluminized the tube in the first place this hazard would have been reduced considerably and the pictures would have been spectacularly brighter!

Cliff

[nasadowsk]

It's what's stated in the RCA tube manual. *shrug*