Did someone mod it to freeplay?

Does the credit unit stepdown coil get energized? Otherwise sounds straigtforward but I'd have to see the schematic.

As HowardR suggests, if the step down solenoid is being energized then you have a mechanical problem. With the power off you can push in the step down plunger and let it go. It should subtract a credit under spring power alone.

If that's working then there are a few switches to check:

Target Alpha segment (resized).jpg

If the total play meter is advancing when you add a player then the switch on the S relay is working. Check the other three switches circled. The V relay is the Replay Button Relay and it should fire when you hit the replay button if you have credits on the game.

Note that the Zero Pos. Replay Unit switch should be closed if you have credits showing and opened by a post on the credit wheel when the credits step down to 0.

/Mark