I finally got a chance to spend more time on this one. Opened it up, cleaned the pot, played around, and drew up a first draft schematic.
I've attached some photos of the interiors. It's clearly been modified, three transistors have been changed (solder-spliced to the dead legs of the originals), and one (presumably original) four-leg metal-can transistor that I can't identify or figure out the pinout. The replacement transistors say "CBS 1232" on them, but I can't find a datasheet for that part, and I can't make out any markings on the four-leg guy.
The filter capacitors also appear unoriginal and the values seem to have been chosen at random as far as I can tell.
Anyone care to make sense of my schematic? I've double checked it with my meter, but I'm sure there remain errors. What's the deal with the four leg transistor?
EDIT: I meant to say, after playing it a bit, and running the pot back and forth a hundred times, I do get a weak reverb signal from it, as well as a slightly boosted dry signal.
More photos of the guts are here:
https://imgur.com/a/527Kr9iIt has a tiny tank inside, but I don't know how to measure the coils. I'd like to get it back to it's original shape, but if not I suppose I can build a different reverb circuit into the box, maybe with something like this:
https://www.tubesandmore.com/products/reverb-tank-accutronics-amc2bf-2-spring