Fitting a new coil that came with a diode

Steps

• For any coil except a flipper, clip the diode off the new coil; the driver board already has one.
• Then the wires can go on either lug.
• If you leave the diode on, the power wire must go on the banded-end lug and the ground wire (green) on the non-banded lug.
• Reversed wires act like a shorted diode and can damage the driver transistor.

Systems

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

Related tips

• Testing the diode on a coil
• Why WPC coil diodes are on the driver board
• WPC coils need no diode except the flippers
• Driver transistor dies after fitting a coil that has a diode
• Coil diode polarity
• Checking for power at a coil with the game on
• Grounding test for WPC coils 1-8
• Spotting the +50 V wire on a coil

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