Closing switch 18 also shows switches 12 and 13 (same column), and another mini playfield switch does the same. Unplugging the 10 opto board makes the extra switches go away, which points the wrong way, at the opto board.
One switch also triggers others in its column: bent diode on the mini playfield
Cause: A switch diode on the mini playfield had been bent over by airballs and was touching where it should not, shorting the matrix.
Checks
- Looking at the mini playfield from the player's position, check the diode on the bottom right switch and make sure it only touches its own solder points.
- Inspect every switch diode on the mini playfield for damage.
Fix
- Straighten or replace the damaged diode and make sure it cannot touch neighbouring parts.
Systems
Games
Related tips
- Mini playfield switches misread and one switch shows as another: bad diode and miswire
- Indiana Jones ninth switch column
- Ninth switch column on Twilight Zone, Indiana Jones and STNG
- Whole switch column dead after a diode went in backwards: column driver chip
- Two or more unrelated switches trigger together
- A whole switch row or column is dead
- A switch does not register in the switch test
- Indiana Jones: balls keep ejecting from a crushed mini-playfield switch
Source: Pinball Repair help group!! (Facebook group)