A newly fitted switch seems to work but appears as a different number (for example 68 instead of 48), or one switch shows as several in switch test.

A replaced switch registers under the wrong number

Cause: The row and column wires were reversed, or the switch was wired completely backwards, when it was replaced.

Checks

• Compare the number shown in switch test with the manual.

Fix

• Rewire the switch per the manual.

Systems

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

Related tips

• A whole switch row or column is dead
• A switch does not register in the switch test
• Several switches in one row or column dead: a broken daisy-chain wire
• "Check Switch ##" message
• One switch does not work
• Several switches in one row never register: broken row wire at another switch
• Lifting targets give a motor up error: broken wires and a bad up switch
• Reading WPC switch numbers and the switch test display

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