TMCC loco won't move, flashing marker lights

Since the marker lights are driven by the Odyssey I DCDS, my guess is something is overloading that board and causing the DC power to cycle on/off.  I'd start by checking the motor for free movement, then unplug it and connect DC to the motor to see if it runs without drawing excessive current.  If the motor is stalled, that's what you're likely to see.  Failing any motor or mechanical binding, my top suspect would be the DCDS Odyssey driver board.

gunrunnerjohn posted:

Since the marker lights are driven by the Odyssey I DCDS, my guess is something is overloading that board and causing the DC power to cycle on/off.  I'd start by checking the motor for free movement, then unplug it and connect DC to the motor to see if it runs without drawing excessive current.  If the motor is stalled, that's what you're likely to see.  Failing any motor or mechanical binding, my top suspect would be the DCDS Odyssey driver board.

I also tried it with the Odyssey switch turned off, again to no avail.  Should that have changed anything if the DCDS board is the issue?

No, my suspicion is that either the motor or drivetrain is binding, or the output drivers on the DCDS are shorted.  That doesn't change if you turn off speed control.

Update: the engine has now started to move, albeit very jerkily (sometimes won't even make a full turn of the drivers, sometimes it does make a full turn of the drivers), and the marker lights are still flashing while the throttle is turned up.  Didn't do anything differently from yesterday.  What does this mean potentially?

I’d suspect there’s something in the drivetrain binding. A loose eccentric crank can do it sometimes. 

I'm with Zachariah, either binding in the drivetrain or a bad motor.  I'd be thinking drivetrain if it were me.

You probably need the buffer that gunner John can provide. That buffer has made my 2400 sq ft layout fun go operate which was a mess before. I was selling engines before who h would blink and stop in their tracks but now run great with the buffer from gunrunner John. Its the best thing since sliced bread. 

I think in this case, he has a real problem with the locomotive, most likely mechanical.

Thank you for the diagnosis John and Zachariah!