Three weeks ago, I, too, bought a basket case of a Hokus Pokus. I learned one valuable lesson; learn how to read schematics. I was tracking and fixing disconnected wires in minutes. Further, to diagnose any issue. I start by finding the wire color and start tracing the path. Playfield is across the top, scoring in the middle, and lighting on the bottom. The thick black lines, left to right are the sources of power. Keep the schematics on the table, keep looking at them, and things will make sense. My machine is very close to being finished. Please update this post. I may be able to help you.

Mine is now up and running, as of 2 hours ago. The main problems with this one were the stepper units, filthy contacts, and very dirty jones plugs. There's a walk around video on Youtube that I posted last night.

ABCD inserts were put in today. Thank you for sharing my video HowardR.