Pressing start launches all four balls and the launcher keeps cycling, and the flippers do nothing during play, although they fire in coil test. Switch test shows no balls in the trough.

Launches all the balls and flippers won't work: debris in the trough, optos out of line

Cause: A broken piece of a playfield toy was lodged in the trough and the launcher optos were out of alignment, so the game never saw the balls and never properly started the game; the flippers stay disabled until it does.

Checks

• Look in the trough for debris or broken parts.
• In switch test, check every trough and launch opto registers as balls are added and removed.

Fix

• Remove the debris and realign the trough and launcher optos so each one reads properly.

Systems

• Sega/Stern Whitestar

Games

• Harley-Davidson (2nd Edition)

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