The device kicks normally but no points are added.

Pop bumper or sling fires but does not score

Cause: The separate scoring switch on the device (the one that is in the switch matrix) is out of adjustment or broken.

Checks

• Close the scoring switch by hand in the switch test and see if its number shows.

Fix

• Adjust, clean or replace the scoring switch.

Systems

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

Related tips

• The switch test cannot check pop and sling trigger switches
• A drop target switch registers when the lower pop fires: replace the pop coil
• Pop bumpers do not show in switch test: pull the ring down to test them
• Switch matrix chip and PIA keep failing: coil voltage leaking into the matrix
• Hitting the left pop bumpers tilts the game: failed PIA on the MPU

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