ie the yellow PVC? wrapper often seen around the windings or frame, more so
than mains f transformers.

Is it always yellow?
If light brown with other indications that there was an excessive load and
general overheating, would a light brown colouring mean it was overcooked
and shorted turns a possibility? An original one for this model not seen, so
no idea if it should be light brown or the ubiquitous yellow.

I will try cooking some of the yellow tape stripped from a scrapper.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/