That's odd, they're not on the same circuit:
The Space Station D light has two other lights wired in parallel to it. Are they stuck on too? Or burned out?
Have you checked the wiring against the schematic? Are the two bulbs that are stuck on wired as shown above or are they wired together?
All of the bulbs should have a 50/white wire on one lug. The D TB light should have a 65/brown-white wire on the other lug. The other three D lights should have a 13/red-yellow wire on the other lug.
What about the other two bulbs on that same circuit, Top Lane D and Mushroom Bumper D? Do they have the same wire colors as the Space Station D? The schematic says they're wired in parallel so they should all go on/off together which isn't what you've described. Is that the way they're wired?
I suspect that two of the three D bulbs (not the D pop bumper bulb) are burnt out, otherwise all three should be stuck on.
There may be a short in your Space Station unit. If you desolder the 30/yellow wire from the unit the D light should go out. If it does you could check the resistances (with the game unplugged) between the solder lug where the yellow wire attaches to the unit and the four wires that go out to the ABCD lights:
A lights: 23/blue-yellow wire
B lights: 25/blue-white wire
C lights: 27/blue-orange wire
D lights: 13/red-yellow wire
First take measurements for the A lights since those seem to work. Step the stepper through all 4 positions. You should see the resistance between the yellow wire and the blue-yellow wire drop to something less than 1 ohms when the unit is in the A position. If you don't get the same results for the other three lights I'd look carefully at the step unit, wipers, solder lugs, etc.
Quoted from ibis:
I metered the A, B and C lights from their respected place on the switch stack and they show no real change in Ohms to any of their associated lights on the play field.
I don't understand what you measured.
Have another look at the schematic in reply #2. What I intended was that you could clip your meter to the 30/yellow wire leading into the Space Station Unit at the bottom left, and to the 23/blue-yellow wire on the unit that leads out to the A lights (as an example). Unplug your game, set the meter to measure resistance and manually advance the stepper. You should be able to see the resistance drop to a low value (less than 1 ohm) when the Space Station Unit wiper is in position to turn on the A lights. That probably happens in every 4th position of the stepper. The other three wiper positions should have some higher resistance value.
If that works for the A lights, repeat the experiment for the other three wires leading to the B, C and D lights. If there is a short in the Space Station Unit for the D lights you probably won't see the resistance change on the 13/red-yellow wire on the D lights the way it did for the 23/blue-yellow wire on the A lights.
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