UDN display driver chips

The master display board has at least four UDN7180A segment drivers (A means plastic case) and at least four UDN6118A-1 digit drivers. The older UDN6184A can be replaced by a UDN6118A-1. Prefer the A-1 version, rated 100 V, over the plain 90 V UDN6118A. Both chips are no longer made, so handle them with care.

Systems

• Williams System 11
• Williams System 11A
• Williams System 11B
• Williams System 11C

Related tips

• UDN display driver chips
• Characters missing from a display
• Same segment missing across one 16-digit display
• Checking a UDN driver with a logic probe and scope
• Display board chips shown as 4050 are really 4049
• One segment lit on many characters of the top display: unsoldered leg on a driver chip
• System 9 versus System 11 display data
• Testing UDN6118/UDN7180 chips for shorts

Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell