[glyphmon]

Rod and Mike,

Thanks.  That's why I asked about the schematic clues.  The diagram does specify which are electrolytic, but again no polarity.  I find the Philco part lists to be much more helpful in identifying types and other characteristics than the RCA ones, at least for 1937.

None of these cans actually had the paper insulating wrap on them - they were self contained and screwed tight through the chassis, metal to metal, so straightforward in a sense, with but two wires coming out of the hole in the center.   Two of the three did in fact have red and black wires, so I simply matched black to negative and red to positive on those (C16 and C30).  The "as-found" connection points for C31 were: black to the end of the candohm (R17); and white (red?) to a mid-air junction between the 2nd IF transformer and 6F6 tube, so I expect I'll do the same and route negative to the previous connection point for the black wire.

I had already gotten the 450V for all of them based on previous comments, but I did go with a presumably heavier-duty 10 uF for C30 since it was available and 34 cents more.  I could certainly set 500V as a standard for replacing electrolytics in the future unless a higher value is clearly called for.

And of course, I would welcome a visit from any experts that want to visit Maine.  I happen to be about a 45 minute drive from the primary section of Acadia National Park and I work in the park's smaller, mainland piece, so I'm conveniently located.

Best wishes,
Roy