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MrFixr55,

I do have a longish wire antenna attached but it's compacted for now, not strung out in a straight line, but I don't have a direct way at the moment to hook up a ground, unless we think running a wire into a ground prong at an outlet is sufficient.

The voltage at the R14/R15 junction with both tubes installed is 175 give or take.  When the tubes were removed, this climbed to 218.

As I look at the schematic, maybe I'm wrong, but I think 170 is what's expected at that junction because that is what's specified in the tube voltage diagram as coming from C16, so I feel like 175 is pretty much okay for that side.

So, doing the same math, we need a 75V drop from what's present, or probably better to say a 70V drop from expected, which should mean a 15.9K (say 16K?) resistance?  But the schematic, diagram, parts list, and resistors say 22K in both name and in testing.  I could accept an error in the documentation, but I wouldn't think it would be consistent across all of them.

I don't have spare tubes, but I could order some.  Though, maybe I'd find one or both of these in one of the other sets I haven't touched yet.  Of course, they wouldn't be tested either.  I'll take a peek to see what's in there in case I'm lucky. I presently have no other RCA radios so they will at least probably be a different brand if the same tube type.  Edit:  The 37-620 sitting right next to it has a glass 6A8 and a 6K7MGT which was lucky.  The readings changed slightly - up to 66V on pin 4 and 173 on R14/R15 junction.  Not enough to make me think that this is the root issue.  I cannot of course vouch that these two other tubes are 100% good, but only that the last person who worked on it before me put the 6K7MGT in (as it is a newer Realistic brand that was not in the radio when I first took it to be serviced), and I would hope he verified the other tubes while he was at it.

As far as sensitivity and quietness, it's hard for me to judge.  I managed to tune in only one AM station from about 15 miles away.  The next closest is about 28 miles away, and from there is Boston at over 200.  On shortwave, I could receive from Romania enough for my wife to understand what was being said, and there were other stations I've come across at different times.  There is much more activity on shortwave, or at least more points on the dial where it sounds like the radio is picking something up.  The volume hasn't been especially quiet, though I don't know that I had to turn it up to max.  Certainly when I used my AM transmitter in the same room it was plenty loud without max volume.

Best wishes,
Roy