One coil never fires in play or in the solenoid test; the fuse is fine.

A coil does nothing although its fuse is good

Cause: A broken coil winding (often at the solder lug), a broken power wire somewhere upstream in the daisy chain, or a driver transistor that has failed open.

Checks

• Meter on DC volts, black lead to the metal side rail: each coil lug should show about 20-75 V.
• No voltage on either lug: check the fuses and trace the power wire back through the coils it is chained from.
• Voltage on one lug only: the coil winding is broken.

Fix

• A winding broken right at the lug can sometimes be unwound one turn, sanded clear of enamel and resoldered; otherwise replace the coil.
• If the coil and power are good, test and replace the driver transistor.

Systems

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

Related tips

• No coils work at all, fuses are good
• One coil will not fire
• One coil does nothing in the solenoid test
• A solenoid will not fire in the solenoid test
• No 50 V coils work
• Firing each coil from the WPC solenoid test
• Two or more coils fire together
• Press Start during the solenoid test for a coil's wiring details

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