I have been modelling in HO for 50 years, have a large layout and too many locomotives to convert to DCC at this stage. I also have a number of Bachmann consolidations and since they run very well and are good value I just purchased another. It was advertised as "DCC ON BOARD" and it was stated that it was "backward-compatable" to DC operation.

I looked at the shematic drawing included with the locomotive and seeing no specific instructions for operating in DC, I set the unit on the track. I could hear the motor humming and eventually it took a few staggering jerky steps. I tried reversing with the same results.

I then assumed maybe there was something I had to do to convert back to DC. I again studied the drawing and noted a small box in the bottom left hand corner titled "For dummy plug installation." I thought maybe that would be the answer. I opened the tender and removed the decoder as per instructions. The insertion of the dummy pins was to be according to the numbers 8, 5, 4 and 1 on the drawing. However there were no corresponding numbers on the plug and play base. Therefore I tried all possible combinations to find that there was no difference in the operation of the locomotive. In short, in any of these modes it merely humms and sometimes makes small jerking motions.
Is my problem electrical or mechanical? Is the locomotive simply defective?