just take your time, take a lot of pics, go slow and be gentle when moving around the chassis. The wires are very old and quite brittle, esp all the connections to the tuner and pots located near the tuner. Its easy to break one. Note the strain reliefs with lots of pics so you can get them back where they belong. I assume you know about how the tuner mounts to the back of the chassis (if its the hard wired in kind) for servicing out of the set.
becare hooking and unhooking up the speaker, its easy to break off the little term connectors on the speaker, same goes for the wires that attach to the transformer.
Just remember there is not rush, better to go slow and easy, respect your elders
that set has been around a long time.