OK so now that 2 of my girls are in school again, and the other one actually napped (YAY FREE TIME) I could futz with this again. I had gone to the guitar store to find a used P90 (since I don't wanna spend more on a "test" pup than I spent on the entire guitar) They had a GFS humbucker sized P90 that I bought. When I told the guy what I was doing with it, he told me they had an old violin-shaped thing that was too far gone to save, and sold me the pickups off of that for $7. Can't beat that, he even checked 'em out with his tester before I bought them so I knew they worked. I got the 90 into the neck (middle?) space(It didn't fit into the bridge route, and I didn't want to enlarge it), messed with the wiring aaaaaand...
All I got was a tiny bit of noise if I pulled up on the pot and kind of shook it. I tried changing all the wires around and got nothing. I think I have to see if I jarred something loose on my control plate or something. And I realize my plate and the original guardplate don't line up. I do have a chunk of guard plate material, and my mother-in-law has a band saw she'll let me use, if I get a new blade for it. I could try to make a new guardplate since this project is already spiraling out of control (or just circling the drain, ha ha)
I did put the violin bass pups in, they were exactly the same size as what I already have. Except they work... I did get the bridge pup to work, that made plenty of sound with the "tap on the polepiece" test. The neck one, not so much.
I really wanna know what my fake 90 will sound like, so I'll play with the wiring some more and get back to you. Hopefully before Christmas...
Playing this reminded me how much I like this bass, even though I spent more time now filling dents and drilling holes into it rather than actually PLAYING it.