Ball missing messages, or more than one ball put into the shooter lane.

"Ball missing" errors or extra balls served (roller switch trough)

Cause: A damaged roller microswitch in the five or six ball trough. Often the last one or two balls in do not roll far enough onto their switch.

Checks

• Check that each roller switch moves freely and its roller turns.

Fix

• Adjust the switch if possible; otherwise replace it. Do not oil it.

Systems

• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Games

• Batman Forever
• Baywatch
• Guns N' Roses
• Jurassic Park
• Last Action Hero
• Mary Shelley's Frankenstein
• Maverick
• Tales from the Crypt
• The Who's Tommy Pinball Wizard
• WWF Royal Rumble

Related tips

• Trough roller switch diodes get crushed
• Ball trough optos from Baywatch on
• Two balls served at the start of a game
• Ball ends early for no reason: missing switch diodes on the ramp switches
• Jurassic Park: "six balls missing"
• Three-ball troughs on early Data East games
• Right shooter lane kicker often fails the skill shot: ball sits off-centre
• Outhole kicker bounces the ball back off the apron: drain switch bent too high

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)