Checking for power at a coil with the game on

Steps

• Game on in attract mode, playfield raised; on 1993 and later games keep the coin door closed.
• Meter on DC volts (100 V range), black lead on the metal side rail.
• Probe each coil lug with the red lead: both should read about 20-80 V DC. On a flipper coil test the two outer lugs.
• No voltage on either lug: power is not reaching the coil; trace the power wire for a break.
• Voltage on one lug only of a two-lug coil: the winding is broken.

Coil circuits carry about 50 V DC; touching the clip to the wrong lug shorts the supply and can blow a fuse.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• A coil stays energized
• Coil-not-working checklist
• Grounding test for WPC coils 1-8
• Coil pulls in as soon as the game is switched on
• Spotting the +50 V wire on a coil
• No 50 V coils work
• Checking the coil supply at TP6
• Coin-door interlock cuts coil power on 1993 and later games

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)