One coil or flash lamp, or a group of them, works intermittently or not at all.

Single coils or flashers dead on games with a fuse board

Cause: Blown fuse or cracked solder joints on the backbox fuse board.

Checks

• Check each fuse on the fuse board (inside left of the backbox).
• Look for cracked or cold joints on the board's connectors.

Fix

• Replace blown fuses and reflow the fuse board's solder joints.

Unplug the game before pulling fuses or working on the power supply; the transformer side carries line voltage.

Systems

• Bally 6803

Games

• Atlantis
• Blackwater 100
• Dungeons & Dragons
• Escape from the Lost World
• Heavy Metal Meltdown
• Special Force

Related tips

• Which 6803 games have a backbox fuse board
• Switches score but no coil or flipper fires: blown 5 A fuse on a backbox board
• Strange intermittent faults from power supply solder joints
• Coil fuse FU1 blows the moment the game is switched on
• Fuse values to keep for 6803 games
• Check every power supply fuse before first power-up

Source: Repairing Bally 6803 Pinball Games from 1985 to 1989, Clay Harrell (pinrepair.com)