There is a circular Bakelite set of contacts underneath the Roto Target you can loosen it and rotate it in order for the contacts to line up then it will score I had the same problem with my dancing lady

Check to see that all the springs underneath are attached. There should be an anti-reverse pawl lever, and if the spring is off or missing, the roto unit won't stop in the right position.

I've found this helpful.

http://arcarc.xmission.com/Newsletters/Gottlieb%20On-Target%20Newsletters/ontarget_april81.pdf

IMG_0050 (resized).JPG

take the plastic off the top and with a long screw driver you can access the screws to loosen. If you watch the lifters, you can spot when they are on the rivets

Yes, looking at the diagram the red-white should be hot as long as you have power to everything else... there is a contact on the ball unit that drives all the pf 30v stuff.

Something is wrong in the way you're measuring. You are probing the side common to all the switches, you should put your clip lead there and probe the other side of the switch. Not sure how the wire you're clipped to is involved in the circuit.

A minor note, the one screw that holds a jumper, if you inadvertently tension the jumper then shoe doesnt float and the far right target doesnt score. Im sure somebody else will hit this.