The dinosaur does not turn left or right, works only sometimes, or its mouth will not open and close.

Jurassic Park: T-rex will not turn or its mouth will not grab the ball

Cause: Cracked header pin joints on the small relay board under the playfield that reverses the dinosaur; or broken wires in the cable running inside the dinosaur (the usual cause when the mouth fails).

Checks

• Reflow the relay board header pins before anything else.
• Check continuity of each wire in the cable through the dinosaur while moving it.
• In the switch test, check the left, right and centre position switches as the dinosaur moves.

Fix

• Resolder the header pins, repair or replace the cable, and fix any position switch that does not register.

Systems

• Data East CPU Version 3

Games

• Jurassic Park

Related tips

• Jurassic Park: "six balls missing"
• Jurassic Park: CPU code 5.10 protects the T-Rex motor
• Jurassic Park can have either PPB
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• Jurassic Park, Last Action Hero, Tales from the Crypt: random resets in play
• Jurassic Park, Last Action Hero, Tales from the Crypt: flipper dead from its EOS switch
• Jurassic Park, Last Action Hero: flipper return springs break
• Jurassic Park: coils fire at random, fuses blow, switch matrix shorts

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