disconecting the magnet will not stop the boom baloon working my guess is the leaf switch that is stuck on or badly adjusted or maybe the wire has droped off the solanoid both can be checked in the test menu
it is possable that the magnet has gone bad in the ring master dont think they are that expensive also check the wire that runs to it this often kinks and breaks where the ring master goes up and down
stick with trying to mend it i am sure you will get there in the end