[RedRobot]

Got some parts, had some adventures.

Prep:
1. Replaced rotting wire for the pilot and dial bulbs, rebuilt the sockets as per the Library page, put in new bulbs: it lights up all pretty again.
2. Cleaned band switcher by applying contact cleaner and switching back and forth several times.
3. Separated out the two wires of a speaker cable, ran one to a water pipe in the basement, and the other out the back door along the hedge to the garage. The goal was just a test, not serious antenna construction.
4. Disconnected the loop antenna, put the ground on screw terminal #3, and tried the antenna wire variously on #2, #4, and pin 3 of the external antenna connector. They were roughly equivalent in the results.

Results:
1. AM reception not exactly better or worse than the loop. I get a few more stations but also more static.  But one big improvement is that the hum peaking at 600 kHz isn't nearly so bad and there's even a weak station in that range. At least it confirms that the interference source is somewhere indoors I think.
2. Shortwave bands still silent. Maybe I need to clean the switch more thoroughly? I'm looking up what it's supposed to look like so I can compare the state of mine.
3. While checking that the ground was connected right my multimeter showed the chassis being at 60V whenever plugged in, off or on. It wasn't doing that before, and I had just been unknowingly touching the chassis to tinker with antenna leads without being shocked or anything. I hadn't changed wiring other than the new lights that are all on the 6V circuit. Could that be something that went screwy with the safety caps?

Also ordered the audio jack, switch, and a fuse holder, they should arrive soon. Went with a  screw type since it's easier to change from outside, though contingent on opening that one knockout hole in the chassis.