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The tuning control has a rubber wheel on the shaft. This rubs on the edge of the tuning wheel. This in turn has the cord to move the dial pointer. The problem is that the rubber has gone rotten, and it is also slipping on the shaft. No chance of a replacement.

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I used to replace those rubber roller things with several layers of heatshrink tubing.

I've used fuse holders like this tucked under the chassis to fuse the incoming mains voltage. If the power transformer is about to short out (or if say the filter cap goes bad and places a short on the rectifier tube and in turn the power transformer) the fuse will blow before hopefully! the transformer.

Unfortunately when the fuse blows, it is usually too late for the transformer but that is the way of the world. It's better to have a transformer almost cash in than to let it sit and glow red hot and make matters worse. I'll admit that I haven't fused every radio I own, and there's more than 250 of them, but the ones I play on a regular basis do have fuses installed. I usually use a 3A cartridge in these holders. Small enough to react to a short, big enough to not blow for the hell of it.

And yes, reheated transformer varnish doesn't smell nice.

A thermal fuse in contact with the windings (and appropriately insulated) is the only sure way to protect relatively small transformers.

Just remember you can't solder to these things!

In my experience in performing warrantee repairs on hundreds of mains operated small appliances, I find that the mains primary winding is the fuse!

Have had similar problems where the rubber on the drives of a mechanical tacho turned to jelly like that of the cover of my GPS.

In the case of the tacho & a few other things, I have been able to buy neoprene at an engineering supplier & cut & grind new ones, often using "Burrs" in a die grinder.