Problems with PS3

Chances are you need to ensure pickups clean and oiled.  They can corrode internally to the roller and prevent good operation.  The other thing is to inspect internal truck wires especially ground wire with black screw.  Some need coating scraped off bottom of screw to get good ground.  Makes sure both trucks have continuity.

I have also seen folks add extra traction tire to non traction tire wheels which means less ability to get a good outside rail power pickup.   G

I suspect a bad connection on the wireless drawbar.  Make sure that both ends are connected well and fully seated.  I’ve had similar issues even though I “knew” the connections were tight.  Even if a connection is unseated by a very tiny gap, it can cause the problems you are experiencing.

Also, does the loco have a trailing truck that could possibly contact the exposed contacts on the cab end of the drawbar causing a short and fried board?  Even if it has a plastic insulator, that can rotate out of position.  You will want to put some liquid tape on the exposed contacts.