The number shown briefly at power-on on WPC-S games

On security PIC games, the PIC serial number appears on the display for a few seconds at power-on; it identifies the distributor. Some games have a small dot matrix power-delay board added that keeps the display off for about 10 seconds so the number is never seen; a late-lighting display can be that board rather than a fault.

Systems

• WPC-Security (WPC-S)
• WPC-95

Related tips

• What the WPC dot matrix controller does
• Which dot matrix displays fit WPC games
• Dot matrix display power connector pinout and voltages

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