Each time the game is switched on, it ejects every ball into the shooter lane and fires them out; after they drain back the game plays normally.

All balls are kicked into the shooter lane at power-up: trough opto board solder joints

Cause: At power-up the game counts balls with the trough optos. One opto pair read as stuck because of cracked solder joints on the trough opto board, so the game didn't trust the count and emptied the trough to recount.

Checks

• In switch test, check every trough opto with the trough full and empty; look for one that stays on.
• Inspect the trough opto boards for cracked joints, especially at the header pins.

Fix

• Reflow the solder joints on the trough opto boards, or replace the boards (they are inexpensive).

Systems

• Sega/Stern Whitestar

Games

• Monopoly

Related tips

• Drained ball not seen, game stalls: VUK opto stuck closed, replace the transmitter

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