IJ Switch matrix
IJ Switch Matrix.png
Typically, if you are getting player adds, its because the Mini Playfield Bottom Outhole diode is crushed/shorted. The diode can be hit by the ball.
If you are getting slam tilts, you may check the other diodes in the row and column listed above... Columns 1 and 2, rows 1 and 3.
Edit: For instance, Row 1 column 1 (single drop top) could affect both slam tilt AND start button. So could the ticket opto.. which I might assume you don't have...
Hope this helps,
-Wes