Install the Andre Boot test ROM

Steps

• Turn the power off.
• Unplug 1J3, 1J4, 1J5, 1J6 and 1J7 (and 1J8 on System 7), and remove ROM 2.
• Burn the test code into a 2716 (or the 2732/2532 version for System 7) and fit it at IC17.
• System 7 only: fit jumpers W23, W12 and W9.
• Power on: expect nine flashes with the driver board (ten on System 7) and five without.

Systems

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

Related tips

• Blanking stays low: timer, C31 and Q5
• "Flipper ROMs" have nothing to do with the flippers
• Which System 3 to 7 games use which flipper ROM system
• System 3 CPU board ROM layout
• System 7 CPU ROM sockets
• System 4 CPU board changes and ROM layout
• System 6 CPU board changes and ROM layout
• Firepower CPU ROM configuration and jumpers

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