Oh, I'm going to have to do a teardown with photos and post them. This is a nice-looking piece of kit. It's in good shape, too.
Sadly, it uses a pair of large beam pentodes for voltage regulation, and one of them is cracked around the anode cap, so I'm waiting for the replacement to arrive. Plenty of time to clean it up and take pictures in the meantime, I guess. I don't really want to start up a 3kV power supply without cleaning the dust out.
It's beautifully simple, too, so I really don't think I need a manual. I might trace out the PCB and get a schematic.
I'll probably replace the electrolytic caps as well. 1974 isn't too bad, but it's not like they're really expensive.