After pressing start the score motor runs and runs and the game never becomes ready.

Score motor keeps running after start is pressed

Cause: The game is waiting for a job it can't finish: most often one of the two zero-position switches on a score reel is out of adjustment, or a stepper unit can't reach its zero position. On Gottlieb, a brake switch that no longer touches its rod, or a worn home switch, also lets the motor overrun.

Checks

• On games with score reels, check both zero-position switches on every reel.
• On games without reels (or if reels look fine), check that each stepper unit resets fully.
• On Gottlieb, find the score motor switch with no wires on it (the brake) and confirm it hits the rod as the motor turns.
• Check the home switch (usually 1C or 4C on Gottlieb) for pitting and gap.

Fix

• Clean and adjust the offending reel or stepper switch.
• Re-gap the brake and home switches.

Systems

• Electro-mechanical

Related tips

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• What the score motor does
• Score motor won't stop turning at power-on: wire broken off a score reel switch stack

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part Two, Clay Harrell (pinrepair.com)