A flipper coil heats up quickly, and the flipper may be weak.

Flipper coil gets very hot: marginal flipper switch reading

Cause: A marginal flipper button reading (often a dirty or failing 4-leg U opto) makes the power side of the coil switch on and off rapidly, so the hold side never takes over.

Checks

• Clean or check the flipper button opto with an infrared card.
• Check the LM339 comparators on the Fliptronics II board (CPU board on WPC-95).

Fix

• Clean or replace the flipper opto; replace the comparator if the opto is good.

Systems

• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• Fliptronics: flipper burns and smells, often stuck up
• New flipper coil runs very hot and blows fuses: bad or reversed coil diodes
• Hot, weak flippers from a dirty four-leg flipper opto
• Fliptronic flipper dead though the button reads
• Flipper coils have two windings
• Weak flipper on an electronic flipper game
• How a two-winding flipper coil works
• Testing the diodes on a flipper coil

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