WPC flags a bad switch at power-on

When WPC decides a switch is faulty it plays around it and lists it in the test report at the next power-up. The report entry clears only after the switch is shown working in the switch test.

Systems

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

Related tips

• WPC direct (grounded) switches
• WPC switch matrix basics
• Switch matrix wire colors (all WPC games)
• Clearing a switch flagged in the power-on test report
• Reading WPC switch numbers and the switch test display
• WPC switch numbers give the column and row
• Finding a switch column shorted to a power circuit
• Finding which switch is shorted to a power circuit (U20 socket probe)

Source: Pinball Machines: How They Work & Troubleshooting, Norbert Snicer