Relay or solenoid?

Both are coils. A relay has a solid core and pulls a hinged armature that operates switches; a solenoid has a hollow core with a moving plunger. EM games use many relays and some are on continuously; solenoids should only fire briefly.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7
• Williams System 9
• Williams System 11
• Williams System 11A
• Williams System 11B
• Williams System 11C
• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95
• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200
• Bally 6803
• Gottlieb System 1
• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B
• Gottlieb System 3
• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b
• Capcom
• Electro-mechanical

Related tips

• Solenoid test also energizes the flipper relay
• Replacing a solenoid coil
• A coil hums continuously
• The solenoid L/R select relay and transistor Q29
• Why relays are used
• Controlled solenoids 9-16
• Testing an under-playfield relay board
• Gottlieb solenoid equivalents

Source: Pinball Machine Care & Maintenance, Bernard B. Kamoroff (Bell Springs Pinball Alley)