Spare UDN7180 at U12 on Pinbot display boards

Games with the D-10877 board (two alphanumeric plus two numeric displays) carry a UDN7180 at U12 that the game does not use. On Pinbot it can be moved into a failed UDN7180 position and U12 left empty. This does not work on every game.

Systems

• Williams System 11A

Games

• Pinbot

Related tips

• Check every segment with the display test
• System 11 alphanumeric displays
• Displays blank but the game plays
• System 9 versus System 11 display data
• Testing UDN6118/UDN7180 chips for shorts
• Check the segment resistors before buying a UDN7180
• Score display layouts across System 11
• Lower the display voltage to 91 V to extend display life

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