OK that is interesting.
Switching something off in the adjustment settings shouldnt have caused a meltdown, because afterall, the setting is designed to give certain parts/features of the game a break incase a tech or a onsite operator wants the game to play even though something might have stopped working.
What was the original reason to turn the magnet features off ? and how many games did u get before it went weird ? was it turned off because u saw the burnt J7 fuse.
