[Arran]

Except that you really don't have that option with the way the series string Predicta chassis are constructed. Not only do they use printed circuit boards but they are mounted over top of a steel chassis so you can't get at the underside without lifting up the boards. To remove the boards you have to undo a number of grounding stakes, and you will need to unwrap a number of wires from around the perimeter of each board. I'm not suggesting replacing everything in one go, but the way these are built pretty much precludes the technique of replacing a few parts, testing, and then replacing more like you can with a hard wired TV or radio, maybe if you rebuilt one board at a time and then put it back in. The power supply section is built onto the steel part of the chassis, so that is one one the few parts that is hard wired, along with most of the H.V stuff, then you have the IF board, and the sweep board, so you can overhaul that part first. I haven't worked on lots of TVs but I have worked on some earlier AC radios that require a similar restoration approach to this, such as the RCA R7 Nipperete style chassis from 1931-33, and their G.E and Westinghouse siblings, those have potted block condensers, terminal boards, and layered wiring.
Regards
Arran