Fire a coil or flashlamp by grounding it

Steps

• With F2 fitted and the game in attract mode, clip one end of a test lead to the side rail.
• Briefly touch the other end to the coil's ground lug (the one with the unbanded diode end and the thinner wire) or the flashlamp's ground lug (the one going to its resistors, usually the socket tip).
• The device should fire. If not, the coil or lamp is faulty.
• Look at the 1N4004 diode while you are there; flashlamps have no diode.

Touching the power lug instead blows the solenoid fuse and may reboot the game.

Systems

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

Related tips

• No solenoid voltage
• Fire a flipper coil by grounding it
• Which way a coil diode goes
• Which way a coil diode goes
• Check the coil diode after replacing a driver
• Old Williams SA/SG 23-850 coils and their AE/AL replacements
• Coil outputs available on System 3-7
• Check every coil resistance before first power-up

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