Hi pbm3
I would like to help - I do not know the pin - I look at ipdb-pictures, manual and schematics. First I ask some questions so I really understand the pin.

Here http://www.ipdb.org/showpic.pl?id=1709&picno=10276 I see 10 rollover buttons in an arc - the rightmost button is lit - below is one of the arrows lit to tell us in what direction the light below the buttons will step. This http://www.ipdb.org/showpic.pl?id=1709&picno=30772 is the area below the playfield. Here http://www.ipdb.org/showpic.pl?id=1709&picno=18916 I see the puck set a bit to the right. Here http://www.ipdb.org/showpic.pl?id=1709&picno=30763 we see it in the backbox.

Question-1: Do playfield-light(s) and Backbox-puck step synchronous - means there are two sighs to inform the player about ONE fact ? (((Or does playfield-light step - but Backbox does not step etc. - means there are two independent / different features ?

Question-2: The goodie in Your pin / Backbox - has it a papertag - what is written on the tag ? Maybe "Advance Unit" ? or what ?

Question-3: The stepping on "Advance-Unit" - does it usually step just ONE step ? - seldom 3 steps ? When a new game starts: Stepping as many steps needed to reach "middle position" ?
Different numbers in stepping ?
In a One-Player-Game: always stepping to the left (respectively always to the right) ? After a goal has been made: The pinball-machine does automatically reset to middle-position ?
In a Two-Player-Game the logic of stepping is ?
When a ball is lost: Does the machine reset the Advance-Unit to "middle position" for next player / next ball ? You see - I do not understand the logic in this unit ...

Question-4: Do You have 1 - better 2 jumper-wires ? You then can manipulate - forcing a good / guaranteed connection (through jumper-wire(s) - the long jumper-wires are clipped-on where we mus clip-on - but the jumper-wires are long - so You can stand at the backbox watching the unit - making contact as You hold the free ends of the two jumper-wires together.

Question-5: Does the description in post-1 means "stepping is good - but when making a goal: RESET is no good" ? Greetings Rolf