Gottlieb 1971 Roller Coaster Pinball - Player Unit

[SummitTrouble]

hello, I've been trying to help a friend through messenger to get his Roller Coaster game to advance ball in play. The player unit has been cleaned and works smooth, and will advance the ball in play a couple times, but then doesn't advance to next rivet on wiper board to position 3 for third ball in play, it stops short. Manually, it works fine every time. The ball elevator switch and ball count switches are fine. Does anyone know what score motor switch may be gapped to wide. 1C or 1A? I don't have schematic and my friend can't read one yet. or post a picture of the appropriate circuit. Normally the score motor isn't the problem, but Player Unit isn't getting a good consistent pulse, so in this case I'm thinking it a switch on the score motor. Any advice is always welcome. Thanks Guys - If I had the machine here, I could figure it out, but it's not here, lol.

[Amechanic]

There are a couple of good groups on Face Book that are just for EM Pinballs. Might be a good place to check. Most slot machines here, but there are a few pinball people too. Good luck.

[SummitTrouble]

I know, EM Pinball on facebook, but I thought I'd give newlife games a shot too, see if anyone knows the switch right of hand, I don't have a schematic, if I did, be done. It's not my machine.