When a ball locks in the treasure chest, the trough keeps kicking balls into the shooter lane, one on top of another, until the game reports a trough malfunction.

Trough fires every ball into the shooter lane after a lock: unsoldered opto

Cause: One pin of the centre trough opto had come unsoldered, so the game couldn't count the balls in the trough.

Checks

• Watch the trough optos in switch test as balls are added and removed.
• Inspect the solder joints on each trough opto (cold joints are common on these boards); clean the optos.

Fix

• Resolder the loose opto pin (or replace the opto).

Systems

• Capcom

Games

• Pinball Magic

Related tips

• Pinball Magic trough serves two or three balls at once

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