Each press of the credit button adds one player up to three players, but the fourth press does nothing. Stepping the coin (player) unit by hand does add the fourth player.

Start button adds players 1 to 3 but never the 4th: adjust the coin unit end switch

Cause: The end-of-stroke switch on the coin unit is opening too early, so the game behaves as if four players are already in.

Checks

• Step the coin unit by hand through each position and watch its end switch.
• See whether the switch opens one step before the last player position.

Fix

• Adjust the coin unit end switch so it only opens at the true last position, and clean its contacts.

EM games have live line voltage in the cabinet; unplug before adjusting switches.

Systems

• Electro-mechanical

Games

• Night Rider (EM)

Related tips

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Source: Pinball Repair help group!! (Facebook group)