None of the flashers light.

No flashers work

Cause: No +20 V: fuse F111 is probably blown, or bridge BR4 has failed.

Checks

• Measure for +20 V at a flasher socket.
• Check F111 and BR4.

Fix

• Replace F111 and BR4 as needed.

Systems

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

Related tips

• One flasher never lights
• No 50 V coils work
• Flasher over the upper right flipper melts its plastic: the flasher is stuck on
• Auto-plunger coil energized as soon as the coin door closes: coil shorted to its bracket
• Launch coil locks on and blows its transistor and fuse every time it is tested
• Left mini-playfield magnet dead, about 8 V at it: F101 blows, shorted Q26
• WPC coils need no diode except the flippers
• Driver transistor dies after fitting a coil that has a diode

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