I was given this MTH Premier 4-4-2 Atlantic for repair. Symptoms where only runs in forward, constant bell and no tender lights/markers.
This was an original PS-2 5V engine that was rich with features using MUX boards to control 2 sets of engine marker, Head light, Cab light, Fire box plus the tender marker and reverse light. $700 engine. The 5V board originally failed and it was sent to a LHS for repair.
When I opened it this is what I had found:
Instead of repairing with a PS-2 3V with 5V connectors, they gutted the engine and just upgraded it using an upgrade kit. This removed the engine markers, cablight and fire box. Removed mux. In the tender removed the markers also, stripped out the harness that allows the shell to be removed and separated from the chassis.
But the worst was they just epoxied the circuit board to the shell, free mounted battery, didn't use a speaker gasket, exposed wire wraps, rat nest wiring, and crushed wires as they put the shell on.
Effectively turning a Premier engine into a RTR engine. So choose your repair facility and tech carefully. G