For the fuse you could call it temporised slow blow fuse, i would say its like a mix of two specs, should blow slower than a fast fuse, but could take some small surge ... thats what they where called in the times ...
Warm chips could say they work, not being defective ... sure check all the voltages points and ripple to be sure, take your time, dont slip a probe while taking measurements, take notes ...
Dont change parts untils you're sure thay have a problem ...
This puppy could last very long
Some Deoxit in the switches, let it do the job, dry the surplus who could get on the board, take your time to do things right
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