I've read as much as I can find relating to 43 volt issues on early Stern machines. I've checked, verified, and replaced the playfield fuse at 1 amp slo-blo. As stated in the title, I have an Alltek MPU and solenoid driver board, plus the BPS018 board from Rottendog. I've verified the wiring with as many photos as I could find here, plus the diagrams that come with those boards.

Here's what it does:
Power on, 7 dings, dim LED on the MPU. Add credits, press start button, manually feed the ball into the shooter lane. I can play the game with flippers, but no solenoids. Check the playfield fuse, yes? I've checked it every time it does this. 1 Amp, slo-blo, tones fine in my hand and when placed in the fuse clips. Playfield fuse seems as good as it could be. Solenoids all move freely, none are locked. I've checked every switch I can find to verify anything under the playfield isn't as it should be. I've manually raised the drop targets, they'll score when struck so the switch works. I've reflowed solder to both sides of the playfield fuse wiring. I've tracked the yellow wire from there all throughout the game and it looks well-connected.

If there's 46v (yeah it's high, is that too high?) going to each coil, why is there no life--ground issue?

The solenoid test cycle only seems to activate the coin lockout coil and the flipper relay. MPU to driver J4 is a bit flaky as I can flex it and it will sometimes not boot.

The 46v was also measured and present at each coil's lug.

While you're here, the audio board cables found on your site are nice, thanks for the quick shipping on them!

*Throws cash in the air*
Woohoo drinks are on me, we have solenoids and the game <kinda> plays now!

Looks like I'm still missing slingshots and the one's digit on all displays, but that's likely more connector issues. Thanks for the help!