Clearing a switch flagged in the power-on test report

A switch that has not closed for a number of games, or is stuck closed, is listed in the test report announced by beeps at power-on. A hard-to-reach target can be falsely flagged. Take off the glass and work the switch by hand during a game or in the switch edges test to clear it.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• After a new U20, work every flagged switch once
• Finding a switch column shorted to a power circuit
• Finding which switch is shorted to a power circuit (U20 socket probe)
• Using the switch edge test
• "Ground Short Row" message
• Switch matrix dead after a screwdriver slip under the playfield
• Row or column "ground short" errors
• How the switch matrix reads a switch

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