Oh, late 50's won't use a 21EP4, it'll use a 90 or 110 degree CRT. The 21EP4 was a 70 degree tube.
Hey, I need a 21EP4
I have a KCS117A chassis portable ("Berkshire" Ammusingly, I picked it up in eastern Mass....). It's a decent enough set, but the sync STILL won't hold very well, and it has those stupid circuit boards that RCA used. A pain to remove from the chassis because of all the random wires, and a pain to work on. Oh yeah, and that chassis is a female dog to remove from the cabinet - you have to pull the CRT out from the FRONT of the set first, and of course, it's a royal pain to discharge before doing this. Then you pull the chassis out. Naturally, there's a zillion screws involved here too.
The tube is a 21CEP4, 110 degree. The yoke looks amazingly modern, too. (It's origional)
Anyway, I'll post a few schematic clips and scope/voltage readings once I get them, to see if I can sort out this synch issue. 1st I want to align the set (or at least rough it in) and see if that helps.
Oh yeah - the tube's shot. Yet another RCA CRT I have that's toasted (3 out of 3 B&W RCA tubes I have are). Anyone got a spare one of these that's good they don't want?