Switch matrix resistor networks and their values
SR9 and SR10: 1k x 4 isolated, 8 pins, switch rows. SR11: 560 ohm x 9 bussed, 10 pins, switch rows. SR3, SR15, SR17: 4.7k x 9 bussed, 10 pins, switch columns. SRC6: 1k resistors with 470 pF capacitors in one pack, switch columns. SR14: 3.3k x 9 bussed, opto row pull-ups, which upset rows if bad. SR8: 1k x 9 bussed. SR9, SR10, SR11, SR3/15/17 and SRC6 fail most.
Systems
Related tips
- How the Williams switch matrix is scanned
- Testing the switch matrix with a logic probe
- System 11 switch matrix: connectors and chips
- Replacing SRC6 with a plain bussed resistor network
- Coin door test buttons and special solenoid switches are outside the matrix
- Random switch closures, random tilts or slam from bad resistor networks
- Row or column error: CPU board or playfield?
- Matrix burned by the lane-change switch touching the flipper EOS switch
Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell