I spent a good portion of the weekend and this evening trying to solve an odd issue with my Bon Voyage . When I get a match game the credit unit would score two credits. At first I thought it was an intermittent contact being made causing the Credit Unit Step Up solenoid to be fire twice. So I set up the playfield on the rotisserie and raised the mounting board out of the cabinet so I would have easy access.
I got to work reviewing the schematic and cleaning/adjusting each contact on every score motor switch, relay and jones plug that could control power in the credit unit. That didn't solve the problem.
So I went back to replicating the problem under more circumstances and identifying the conditions when it occurred. That is when I found the clue. When the credit count was low ( 0, 1, or 2 ) the match score would add two, and sometimes three credits. As the credit count got higher ( 6, 7 or 8 ) the match score would add typically add two credits but sometimes it would only add one. When the credit count was even higher ( 16 or greater ) it would only add one credit.
This led me to believe the problem had something to do with the torsion on the Credit Unit's clock spring. I investigated further and found when the Credit Unit value is a low number the clock spring has a low torsion. As the credit count goes up the clock spring gets wound tighter and the torsion increases.
I then tightened the clock spring two more turns and the problem was gone. I determined the Step Up solenoid is strong enough to kick the Credit Wheel up two or sometimes three credits when the clock spring has low torsion. The game now gives one credit for each match game. PROBLEM SOLVED!!!