Troubleshooting installing a decoder in a HO scale Kato NW2

I’m in the process of installing a Digitrax D123 decoder in a HO scale Kato EMD NW2. Following the link posted by TCS decoders for install guidelines, by isolating the motor, assembling the motor,gears and housing. The problem I’m having is the loco doesn’t respond/move on the track. I have light functions and tested the decoder on another engine as well as testing the decoder just with the Kato motor connected which worked. I don’t know when joining the two halves together is causing the motor to bind, but the halves seem to fit together tight along with the bushings and the motor is isolated with wire connections good. I have installed at least 8 decoders in other engines (Athearn/Atlas) and never had any problems. Looking for suggestions to troubleshoot this.

When you reassembled the mechanism, are you sure you got all of the insulating spacers between the weight halves and that the motor brushes are totally insulated from the frame halves ? From your description it sounds like one of the motor brushes may be making contact with the frame or there is binding in the gears because of improper reassembly.

thanks cacole. Will recheck the alignment of the bushings and motor brushes again. Can it be anything with adjusting the CVs, start voltage, etc. to get the motor to start turning? I hooked up the loco to a separate DC power test track and disconnected the decoder and jumped the pins/wires to the motor and the loco worked test track. This has me puzzled.

Could it be as simple you don’t have the right address for the decoder? If you have not changed the stock address it should be 3. You could try resitting CV 8 to 8 so the decoder is at factory default and address of 3.

I found out that the motor function of the decoder was blown out… I tested it with a decoder from another loco. finally got the Kato NW2 to run! thanks