TYPICALLY, when MTH PS-3 start fine but shutdown on movement (sounds an lights) it is a loss of track power. If just binding it would stop or not move, current draw would go up, but lights, sounds and smoke still would be working until the board sensed this issue and shut down.
So while the pickups to the wheels may be ok, the wiring from them to the PS-3 board is suspect. Ground for 3 rail O is almost always the problem.
I do not have a lot of experience with MTH S so I would have to see it, but the PS-3 board is the same as O Diesel, and this is typical.
Since you do not have tools or experience in this. You can call MTH and see if they would honor the warranty especially with the low hours. If not send to a ASC for repair. G
