I don't think that it is possible that some other voltage regulator is cooler with same load and same input voltage. Unless it works in switching mode. What is for sure not case with L78S05CV - what is "linear voltage regulator" - see data sheets. Actually, it would be hard to make switching one without coil, so hybrid technology - and much bigger price. There are some rules of physics what dictate how much heat will be produced.
Any 8bit repairs, images, cool things, upgrades etc.
There is 2 kind of people: one thinking about moving to Mars after here becomes too bad, the others thinking about how to keep this planet habitable.
Yes, that's just about the time Sinclair stopped selling them. The price drop shown on the box was probably to shift the last of the stock.