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

Jediturtle and andre060, thanks much for prompt reply. Will give it a try this PM. Stay tuned ....

Cleaned the ball trough optos. Checked with a camera to make sure all optos working and then double checked by doing a switch test with a opto and each opto triggered. Reassembled and dropped balls in one after another while watching switch test. 1-2-3-4-5-6 all worked fine. Restarted and problem not resolved. Continues to just recycle. Never loads the cannons, just fire---down the top out hole---repeat. My machine is located next to a beam in the basement so i have to wait for help to move machine away to pull playing field up completely to check diverter so will have to wait until i can get some help with that. A question, how do i do drop target switch test? Target is always down so nothing to press on, switch seems to be below playing field, correct? I can pull the target up, but as soon as i turn machine on, it pops down.

"Manually stage' as in one in each cannon and one in the shooter, or just drop 3 down into the ball trough?

Thanks...

putting a ball in each VUK and starting game (3 balls) didn't work. If i start the game, it recycles balls until i pull one off the playing field. That stops the recycling. Then i press new game and i get message "looking for ball location" or something like that and it continues to do that until i add the 6th ball back to the game. Then when i press credit button, game starts fine, drop target pops up and game works fine, until, game over...ie 3rd ball lost and then it just keeps recycling the balls again.

Think this may be the problem, very difficult to move....will check it out

Took apart, can see the point of binding in the picture because of heat blistering. Can't get sleeve out easily....push harder or need new coil and sleeve?

IMG_2568 (resized).jpg

Coil, sleeve and plunger ordered. Will check optos etc in meantime. Will followup in 4-5 days when have installed coil etc. thanks all for your help....fabulous!

Follow Up...Parts came today, replaced coil, sleeve, plunger. Cleaned etc. All works fine now. Thanks to everybody for their help. Final Diagnosis...diverter problem.

Diverter