The flippers can be used in attract mode or after the game ends.

Pre-Fliptronics: flippers work even with no game running

Cause: The DPDT flipper relay on the driver board completes the ground for all flippers; its driver transistor Q99 (2N5401) is shorted, or jumpers W4 and W5 have been fitted.

Checks

• Test Q99.
• Look for jumpers at W4 and W5 on the driver board; they should not be there.

Fix

• Replace Q99 or remove W4/W5.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix

Related tips

• Replace the pre-driver along with a failed driver transistor
• Which transistor drives which WPC solenoid and lamp circuits
• A coil or flasher energizes as soon as the game is turned on
• Pre-Fliptronics: weak flipper
• Pre-Fliptronics games need a driver board with the flipper relay
• Pre-Fliptronics: a flipper does nothing
• Pre-Fliptronics: flipper lane change does not work
• Flipper buttons not seen by the game (pre-Fliptronics)

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)