Is the D relay energizing for a one-third turn when you drop a target lit for 10x scoring? Are you getting 50 or 500 points on the yellow stand-up targets when they are lit?

Is the D relay energizing for a one-third turn when you drop a target lit for 10x scoring?

When a target is lit for 10x scoring, the D relay should energize for a one-third turn of the score motor. For example, see this highlighted circuit. It shows the D relay getting energized by the #2 drop target getting hit and then staying energized through its own lock-in switch.

The yellow path shows the initial energization of the D relay by the drop target falling. Here are the contacts in this circuit that need to be closed: (1) score motor switch 1C, (2) the "Multiplier Control Unit" wiper board, (3) and the drop target switch.

The green path shows the D relay holding itself after the initial energization. Here are its dependencies: (1) its own lock-in switch, and (2) score motor 1C.

I would have a look at the wiper board on the "Multiplier Control Unit". You might be missing the braid wire that bridges the two fingers for the 24v circuit.

Incidentally, where is the D relay? Is it mounted on the bottom of the playfield or is it on the main board where the score motor is?

Sky Jump D Relay

Turns out it was an unnecessary question because—no matter what—the circuit for the D relay has to go through a jones plug because the drop target switch is on the playfield and the score motor is not. Anyhow, that's one more place to check why the D relay is not energizing: the jones plug. Sometimes there is too much oxidation on the connector or there is a cold solder joint, sometimes inside the male pin. The white-orange wire is the one that goes through the connector.