Fire a flipper coil by grounding it

Steps

• Game on in attract mode. Clip a test lead to the side rail.
• Briefly touch the other end to the middle lug of the flipper coil: it should fire.
• Briefly touch the outer lug that goes to the EOS switch: it should fire again.
• In a game with the button pressed, ground each lug of the cabinet flipper switch: both should fire the flipper. Neither: a broken wire between playfield and button. Only one: dirty or bad cabinet switch.

Never ground the outer lug that carries the main power wire: the flipper fuse blows at once.

Systems

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

Related tips

• Measure a flipper coil
• Replacing a flipper coil
• System 3-7 flipper coils are series wound
• Fitting parallel-wound flipper coils
• Matching a replacement flipper coil by resistance
• WPC flipper coils, weakest to strongest
• Fire a coil or flashlamp by grounding it
• Williams 50 V fat flipper coils ranked by strength

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