Zenith 50kv probe
 

I now have one of these. My question is, what kind of TV's flyback would pack nearly that much of a punch under normal circumstances?

A probe like that comes in handy for those Zenith's with the bad safety cap and the set on a variac!

IIRC some bigger screen SS CRT sets (I'm talking 27"+) had 35KV HV supplies, and some projection sets may also have had higher rated HV supplies.

Definitely projection sets. Home projectors that I have worked on ran up to 35-40 kV on some of them. Some professional/theater CRT projectors ran 70 kV or even more.

Serious X-ray hazard on these things if shielding is disturbed or removed. Not only does the phosphor darken with age, but the faceplate glass itself browns from the radiation exposure just like a 6BK4.

The extra voltage handling could come in handy then as I wouldn't mind having one of those Advent 750 projo sets. Naturally I already have a remote for one.

IIRC, the Advent 700 series sets ran at only 28.5 KV... not very bright, but decent performers for lowered cost early projectors. Chassis made by Electrohome.

jr

What kind of monster would be needed to measure the voltage going through those things?

The units I remember had built-in metering on the operator's panel. If you needed to check against another instrument, something like this would be needed:

http://www.cpshv.com/products/hvp500data.htm