Well, I’m near the end of this saga. I washed the plastic chord button assembly and put a little silicone lube in each of the 96 holes. Can you imagine washing the knobs on a receiver with 96 knobs? Typing that reminded me I cleaned the knobs and slider caps on an old Soundcraft mixer that had maybe to 200… Maybe that’s why they called it the 200!
I also took A LOT of it apart last night and a little oil here and there has everything returning as it should. I spent so much time on this I didn’t get to the coupling caps or fuse adding. Will try and do that today.
And so finally, coupling caps replaced – 2x .047uf 400V MKT caps by ERO from the early 2000s replacing 2x original .047uf 300V caps from the mid 1950’s. Pulled the fuse holder from my big bag of random NOS fuse holders and wired it into one leg to the power switch. Found a 2A slo-blo that I installed. Checked for short – found none, so I powered on. Working well for now. All done!
A response I got that is not here: “A standard cord would be fixed in place, and run through an added fuse (and local switch if needed) and go to ‘2’ and ‘4’. Hopefully your heater voltage is then within spec from your local mains voltage. Do you also have a protective earth?
The chassis ground would also need to be linked over to provide a reference to the speaker output winding of the S6. Not sure how significant a hum loop issue you will get from two mains connections. You may need to google about the reverb control function, and how that interacts with the 30V bias supply.
The PR40 could do with a bit of fault protection imho, as a B+ level fault could cause some collateral damage.”
Gonna worry about the PR40 when I have space to set it up – hopefully sometime in the years to come.