Chris - I'm not familiar with Stern EMs, but since you have had no response as yet, I thought I'd chime in with a suggestion.
Is the score motor still running while the score reels are turning ? Is it one score reel or all of them ?
sounds to me like a wire has been severed.
Stupid suggestion time - with the game off - turn the score motor 180 degrees and turn on the game.
Stupid suggestion #2 - while the score motor is still turning, look for a contact that is not closing.
