Hot chassis' are why my test bench has GFCI protection. The Variacs (360VA and 1.5KVA) are both on their own GFCIs, with the low side on neutral. I also replace EVERY cord with a grounded one before returning to service, even if I leave it floating during testing. Before retesting the chassis potential when it shows hot, I will throw a 500K or so resistor from the chassis to ground or the (confirmed) neutral. This lets me know if the chassis is shorted to live or the level of leakage, narrowing down the source in many cases. I tend not to use isolation transformer in testing, as it can make tracking down faults harder, and it makes me more complacent.

A DVM will read voltage due to the small bleed current of the line filter cap. Normal to see voltage on the chassis. A regular VOM will show a more realistic voltage as it has some load. Still would need to be recapped. I have an S-40B and an S-56. Both have been recapped. The oscillator tubes get weak and they fail to work on the higher bands. There is something about the green glow of the dials that is satisfying. BTW, one of the dial lamps was dead in the S-40A.

Me Being a journeyman machinist I like your machinist tool hauls(picks) much better than your radio picks! Just my opinion. Opinions may vary!