The game reports six balls missing.

Jurassic Park: "six balls missing"

Cause: Driver transistor Q54 has failed. The red 32 V lead on the lock ball coil under the ball arch sits close to a trough mounting screw and can short to it.

Checks

• Test Q54.
• Look at the lock coil solder lug and the trough screw beside it.

Fix

• Replace Q54.
• Insulate the coil lug from the screw with tape or heat shrink.

Systems

• Data East CPU Version 3

Games

• Jurassic Park

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