Looking at the wiring diagram and solenoid schematic page 2, the switch triggered solenoids are controlled here.

IC6 should be tested and confirmed working.

Do you have a logic probe? It's possible to confirm that IC6 is bad or working with a logic probe.

Start a game, probe the output pins of IC6 at pins 3, 8, 11, and 6 while simultaneously closing the switches of left and right slings, and the pops. Any output changes at those pins?

If IC6 checks out, move on to testing IC8, IC9 and IC7 with logic probe.

switch-trigger-solenoid (resized).JPG

It's possible, but since you mentioned the ball lock eject and kicker to the plunger work, that doesn't seem as likely. Unless maybe you left P10 disconnected from J10 on the solenoid board.

With the game off and voltmeter set to ohms, measure continuity from ground strap in the backbox to J10 pins 1 thru 9, all those pins should have low resistance to ground. If that checks out, measure continuity from ground to the emitter legs of all the Tip122 on Q2, Q4, Q6, Q8, Q10, and Q12. I believe that the emitter is the right leg.

Have you tested IC6, 7, 8, and 9 with a logic probe?

Yes, that all looks correct.

That should be safe I think. A small current would flow to ground through R28 while you do that.

Not that different from when IC9 pin 10 pulls it low (when it's working).