The two negative display voltages must be 12 V apart

What matters for the -125 and -113 V supplies (or -115 and -103) is that they sit 12 V apart; -98 and -110 is fine, and -118 should pair with -106. If they are not 12 V apart the controller's high voltage section needs rebuilding. Losing -125 V also loses -113 V. Williams lowered both by 10 V on later boards to make displays last longer.

Systems

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

Related tips

• Dot matrix display supply voltages
• Display voltages low: display or HV section?
• -125 V and -113 V read the same and the display is dark
• Gas discharge displays need high voltage
• Negative HV low and display barely lights
• Outgassed displays and the 5 V supply
• Replace the whole display, not just the glass
• Display shows garbage or nothing though the glass is fine

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