I have a 1961 built-in Revco RG-95-61 refrigerator with a compressor
that finally gave out.  In lieu of reconstructing my entire retro
kitchen, I would like to find a compatible compressor, but Revco got
out of the residential market about 30 years ago.  A local
refrigerator repairman said it would be impossible to find a
replacement compressor.  Is there a modern compressor that will
function satisfactorily or is there some source for antique Revco
parts? A satisfactory answer would include a source, part number, and
price.  An alternate satisfactory answer would be a currently
available model of built-in that would fit the same size hole (24"
deep, 32-1/4" wide, 32-1/4" tall).

Would you be able to look at the compressor? There should be a black
metal tag welded to the side of it. There will be a bunch of numbers.
Let me know.

In looking at the black box that the repairman pointed to when he said
the compressor is not running I find that it is a plastic housing for
the cooling coil that also has a small fan in it. The fan runs fine,
but the coil is not getting cool. The real compressor, off to one side
is running and feels warm to the touch. I suspect I need a refrigerant
recharge instead of a compressor. I can hear liquid circulating. There
is also a relay/timer, perhaps for a defrost cycle that the repairman
did not test. Perhaps I should seek a second opinion from another
refrigeration repairman.

Well there is some good news and some bad news in what you observe.
It's great that the compressor is still running. The compressor may be
fine. The flow you hear is indicating the compressor seems to be
pumping as it should. The downside here is you may have a leak and it
will be most likely the cooling coil rotted out from age. If a leak is
found on the cooling coil and repaired, get a guarantee on the work.
Most of the time more leaks appear soon thereafter and more money out
of your pocket. I usually use a generic replacement coil closest in
size to the original. First, you'll have to find someone who wants to
take the project on. Hope it works out.