Hitting a drop target also registers the eject hole switch (or another switch in the next column), and the eject fires.

Drop target switches also trigger the eject hole: column jumper on wrong switch

Cause: A previous owner had jumpered the drop target switches' column wire to the wrong switch, so they ended up on a neighbouring column.

Checks

• In switch test, close each switch alone and note any extra switch that shows.
• Trace the row and column wires for the affected switches against the manual; look for a column wire colour that is missing where it should be.
• If you can, compare the wiring with another machine of the same model.

Fix

• Move the column jumper to the switch the manual shows (on this game, the standup switch behind the targets on the green/black column).

Systems

• Williams System 4

Games

• Flash

Related tips

• Phantom tilt with two drops down: cold solder on a drop target switch diode
• A ball resting on one switch stops others in its column
• Row or column fault on the playfield
• Switch column or row fault on the driver board
• Switches stuck on: board or playfield?
• Unreliable switches where the ball rests (trough, locks, kickouts)
• The switch test cannot check pop and sling trigger switches
• Board or playfield? The switch test jumper method

Source: Pinball Repair help group!! (Facebook group)