I remember these things, sturdy enough to make an axle-stand for a bus and almost an object lesson in "How a scope works- block by block" with the discrete, fabricated delay lines, bootstrapped relaxation oscillator timebase and multiplicity of supply rails for DC coupling- no such thing as PNP valves! Also the use of an EF86 as EHT series regulator- I like things that are a bit "off the wall".
I hope I'm not teaching anyone to suck eggs here (and apologies if I am) but there is an innocuous-looking Paxolin panel inside (from front, bottom rear right-hand corner) that is fairly bristling with metal-cased components (caps, pots, valve retainer, etc.). Everything on this panel is elevated to EHT (1.75kV) with no warning or covers. I know this might not sound much compared to the macho PDA of later scopes, but it's mains derived and very exposed, therefore very dangerous. Perhaps a "flash" sticker on the rectangular PIO can would be a minimum precaution/reminder,