Newbie seeks advice on Marx 666 repair

I am new to forums and train repair. I am seeking information on the Marx 666, specifically the correct Ohm readings on the field coil, armature and E-Unit, so I can diagnose and attempt repair of the motor.

Last year I replaced a broken reduction gear, but when the holidays rolled around we found that the engine was drawing too much current from the transformer and won’t run. A 12v battery jumpered directly to the armature and field coils makes the motor spin, but the field windings get very hot very fast. I suspect I may need to rewind some of the motor’s coils.

Any advice appreciated, including where is the proper forum.

Try the Classic Toy Trains forum. The Model Railroader Magazine forum is geared more toward HO and N scale trains. Lionel, American Flyer, and Marx are regarded as Classic Toy Trains.