Moneytree One Armed Bandit

[treefrog]

Did you confirm if it was steel pennies that were rejected, e.g. after 1992...? If so, thickness is likely to be the issue. I am not sure these S10 mechs are made or modifications available now as superseded by electronic types. You may be able to play with fine spacers, screw adjustments to get it right, but I suspect this is where you will need to head as I see the magnet has already been removed.