A follow up, I put in the dummy plug and ran on DC test track, no response, lights worked ok.
I put DCC power directly to the motor terminals and it just buzzed, no rotation. I disconnected the light board and applied DC power directly to the motor terminal and motor and drive turn ran great, both directions. I think at this point it is best to drop in a decoder that replaces the light board.
I appreciate the suggestions, I will try that, thanks.
I offered to look at a friend's locomotive, an HO scale Athearn Genesis MP15, i believe these were released back in 2007. DCC only, no sound. He bought it used.
The problem with the locomotive is as follows: the locomotive was running. Then the locomotive did not respond the next time it was ran and so was reprogrammed but still unable to respond. I offered to look at it for him.
I placed loco on my programming track and read back the address just fine. I reset CV8 to 8 to reset the Digitrax 126 (i think) decoder. It then reads back address 03 just fine.
Placed on mainline, directional headlights work in both directions, no other response. Loco does not stutter in any way, does not buzz, no sound at all like it is trying to move, it is simply dead except for front and rear directional lights.
All wiring looks ok and connected to light board (with factory black plastic tabs). I cleaned wheels, track power is getting to the decoder (15 volts)
Drive train is not stuck as I can turn drive shaft. I swapped out the Digitrax decoder and no change.
With power to the decoder (speed increased) i noticed i am getting 7 volts to each terminal on the motor, it stays at 7 volts even if I run the speed to max, I don't know if that is normal or not.
I am suspecting the problem lies in the Athearn light board, but really I am guessing. Are these light boards available from Athearn? is there a drop in decoder for this loco that replaces the light board? my friend is not really wanting sound, although that is what I would do.
I have read a bit about drive train having excess grease, or dried grease. I thought about servicing the drive train as it would not hurt to do so anyway.
I appreciate any thoughts you may have regarding this loco.
thanks.