Score display driver chip substitutes

The obsolete UDN6184A display driver is replaced by the UDN6118A-1; the plain UDN6118A is rated about 85 V and usually works too. The UDN7180A (the A means plastic case) has no cheap substitute.

Systems

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

Related tips

• Display driver board versions
• UDN display driver chips
• Chips that commonly fail on System 3-7 boards
• All score displays dead
• Score displays light then dim or flicker
• Six- and seven-digit score displays
• One score display dead
• Diode-test UDN chips and score glasses for shorts

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