The game boots to a screen saying the coin door is open with coils and flashers disabled (it also reports the slam tilt as stuck), even with the door shut. The test buttons don't work, credits only appear after a reboot, and most of the LEDs on the driver board stay off.

Boots to a coin-door-open message and buttons do nothing: loose serial cable to the PC

Cause: The serial cable connector between the driver board and the PC, at the back near the monitor, had worked loose.

Checks

• Check the serial cable and its connectors at both ends, including at the PC near the monitor.
• Check the coin door wiring to the driver board for a pin pushed out of its connector.
• If the text is in another language, the language can be changed in the settings once the game responds.

Fix

• Reseat and secure the loose serial connector.

Games

• Star Wars Episode I

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