[Raleigh]

Yesterday I pulled the chassis from a 41-255 because I needed to borrow the speaker temporarily. I checked the rubber insulation, and it seems to be fine on almost all the wires. I didn't poke around under the push button coils, where maybe the wire gets hotter, but I was very surprised at the good condition of the wires I could reach easily.

The first couple of Philcos of this vintage I worked on needed every almost wire replaced or sleeved, but I've seen a couple lately in which most of the insulation is in great shape. I wonder what makes the difference from one radio to another? Perhaps different wire suppliers had different recipes for the insulation?

I haven't made a study of it, but it has seemed to me that insulation in hot areas is more crumbly than in other parts of the chassis. Maybe if a radio is used less over its lifetime the wire has less exposure to heat and is less likely to get hard.

Some colors seem to crumble more than others. Black, red, and white always seem bad, while blue and green are better.

Any or all theories welcome!