Which switches are not in the switch matrix

The matrix is 8 columns by 8 rows, up to 64 switches. Outside it are the coin door Auto-up/Manual-down and Advance switches and the six special solenoid trigger switches (pop bumper skirts and slingshot switches). Pops and slings also have a scoring switch that is in the matrix. The flipper relay and special solenoids are active during the switch test.

Systems

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

Related tips

• Logic-probe the switch matrix
• Switch matrix connector pins and their chips
• Driver board switch matrix resistors R204-R211
• Switch matrix column test at 2J2 with Leon's code
• Switch matrix row test at 2J3 with Leon's code
• Whole game dead after working on a flipper EOS switch
• Switch test and audit display behaviour
• The switch test cannot check pop and sling trigger switches

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