Just a fix that might help someone. Might have mentioned this before but my brain is shot and I canāt recall after too long at this 
Was dialling in a few things on Tommy yesterday . The game was occasionally getting confused over the number of balls which messes up things hugely. Not uncommon on DE games of this era.
In case folk arenāt aware as well as the rollover switches in the trough there is also a vertically mounted switch in the trough eject scoop .
The ball needs to activate this switch firmly and keep it activated while it sits there - if there is any slack and the switch closure is borderline then all hell breaks loose with the ball count / feeds out wrong number/ ball searches etc .
Itās a simple matter of bending the actuator arm to get good activation . Or replace the switch if it is failing .
Was dialling in a few things on Tommy yesterday . The game was occasionally getting confused over the number of balls which messes up things hugely. Not uncommon on DE games of this era.
In case folk arenāt aware as well as the rollover switches in the trough there is also a vertically mounted switch in the trough eject scoop .
The ball needs to activate this switch firmly and keep it activated while it sits there - if there is any slack and the switch closure is borderline then all hell breaks loose with the ball count / feeds out wrong number/ ball searches etc .
Itās a simple matter of bending the actuator arm to get good activation . Or replace the switch if it is failing .