Flipper coils run hot during play and the flippers feel weak.

Hot, weak flippers from a dirty four-leg flipper opto

Cause: A dirty or failing four-leg U opto (pre-WPC-95) flickers, feeding the coil short bursts of power continuously and cutting the flipper off quickly when the player really presses the button.

Checks

• Check the flipper opto with an infrared sensor card and watch the button switch in switch test for flicker.

Fix

• Clean the opto or replace it with a correct-sensitivity four-leg U opto.

Systems

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

Related tips

• Fliptronics: flipper coil gets hot after a while of play
• Flipper coil gets very hot: marginal flipper switch reading
• New flipper coil runs very hot and blows fuses: bad or reversed coil diodes
• One flipper dead and its button fails switch test: dirty flipper button opto board
• Lower left flipper weak, worse when the bulldozer runs: cabinet opto board
• Right flipper turns weak after a few games: the coil, even though it measures fine
• Fliptronics: flipper burns and smells, often stuck up
• Flipper coils have two windings

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