After years of flawless play I've developed a problem with STNG that I can't seem to figure out. The problem began when i turned the machine on and it started shooting balls up and "recycling" and never stopped. Test menu showed 3 switch errors 31, Borg Lock; 48, Borg; and 57 top drop. Borg lock and Borg went away after pressing on the switch several times and never has recurred. Top drop more difficult...checked all wires, contacts, replaced fuse F103 (which looked ok), did solenoid test, checked all switches and optos , did a factory reset and even replaced the 3 AA batteries. Nothing seemed to fix that error and the problem of the recycled balls continued. Then, for what ever reason, 3 days ago the error went away and nothing showed up on the test menu.(except time and date not set) Yet the problem or recycling balls continued. I saw the post from 2 years ago about trying 5 balls instead of 6, so I did T18 test (clear all balls) and 6 balls where ejected so there were no lost balls. I took one off the playing field and started up the game. It worked!,and I was able to play the game to completion, and i could see top drop target going up and down as it should. However, when game ended, it didn't stop but started recycling the balls again and again and again. Only stopped when i added the 6th ball back. Problem continues, on start up it just keeps shooting the balls. (note, the top drop target is always down on startup so the balls just go down the top outhole) Any help would be appreciated. thanks