What changed on the System 6A CPU board

System 6A is a small revision of the System 6 board with buffer chips IC9 and IC10 left off. It went into Firepower, Blackout, Scorpion, Algar and Alien Poker.

Systems

• Williams System 6 / 6A

Games

• Algar
• Alien Poker
• Firepower
• Scorpion

Related tips

• Identifying a System 3 to 7 CPU board
• System 6 CPU board test points
• System 6 CPU board jumpers J1 to J6
• A System 7 CPU board can run any System 3 to 7 game
• Run a System 6/7 CPU board on +5 V only
• Installing a single-EPROM adapter in the CPU socket
• Run Firepower on a System 7 CPU board
• Obsolete chips on System 3 to 7 CPU boards

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