Six and seven digit displays

System 3 to 6 games use six-digit gas displays; System 7, Alien Poker and Algar use seven-digit displays with a matching display driver board. Replacement displays with a sealing nipple fit, as most display boards already have a hole for it.

Systems

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

Games

• Algar
• Alien Poker

Related tips

• Six- and seven-digit score displays
• Seven-digit scoring on six-digit displays for green-ROM games
• Displays show only every other digit ("0_0_0")
• Credit display glasses differ between six- and seven-digit games
• New seven-digit glasses may need board changes
• Upgrade R2/R5 and check R1/R4 in the display supply
• Master display board versions
• Which UDN6184 drives which display

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