[Arran]

It may be that someone has worked on that set before, I noticed that it has a newer power cord with brown vinyl insulation, the original was rubber, and they usually go rock hard and crumbly. The insulation used on the power transformer leads was cloth covered, those are usually fine so long as they are not disturbed. What does go bad is the insulation on the wire going into the IF transformers, that should be looked into, as well as some of the point to point wiring.
Regards
Arran