Flippers (and other 24 V coils) do not work in a game.

Flippers dead during play: check the "U" relay

Cause: The flippers get power through the "U" relay, which pulls in at game start. A relay out of alignment may not close, its driver transistor may have failed, or connector A1-J4 is bad.

Checks

• In attract mode, hold the U relay closed by hand: if the flippers now work, the relay or its drive is the fault.
• Check the relay's driver transistor: Q18 on Haunted House, Q17 or Q18 on Black Hole.
• Check A1-J4.

Fix

• Realign or replace the relay, replace the transistor, or repair the connector.

Systems

• Gottlieb System 80

Games

• Black Hole
• Haunted House

Related tips

• Haunted House trap door won't open
• System 80 driver board transistor types
• A CPU-controlled lamp or coil stays on
• Backbox chase lights not running
• How driver board coil transistors are switched
• Haunted House driver board: which transistor runs which coil
• Black Hole driver board: which transistor runs which coil
• Driver board coil connectors A3J4, A3J5 and A3J6 (HH and BH)

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part Two, Clay Harrell (pinrepair.com)