Six- and seven-digit score displays

System 3 to 6 games use six-digit displays and show leading zeros (100 points reads 000100). Alien Poker and Algar (System 6) switched to seven digits, still with leading zeros and no commas. System 7 hides leading zeros and uses the commas.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Games

• Algar
• Alien Poker

Related tips

• Six and seven digit displays
• Displays show only every other digit ("0_0_0")
• Seven-digit scoring on six-digit displays for green-ROM games
• Credit display glasses differ between six- and seven-digit games
• All score displays dead
• Score display driver chip substitutes
• Score displays light then dim or flicker
• One score display dead

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)