Motors stop responding to TMCC commands

Try resetting the R2LC.  Try unseating the r2lc and reseating.  Check connectors especially the motor driver connectors.  At that point a closer look at the DCDR and motor.  I assume this has ODY I? Speed control?  G

Thanks for the good ideas. And yes, I believe it does have Odyssey Speed Control. I will switch it either on or off, depending on how it is currently set, and see if that makes a difference as well.

Thanks for responding. 

I had a similar issue with an Atlas SD40 that was made in 2006. It has TMCC and EOB speed control.

Every once in awhile the engine would slow to a crawl or come to a complete stop on its own while all of the sounds were audible. Occasionally, when I gave a command with my CAB-2 the horn would sound until I performed a reset (AUX1 + 0). 

I emailed Atlas about this and their O scale tech, Bill Seratelli, asked me what my track voltage was. I was running at 19 volts with my PowerHouse 180-watt transformer and LEGACY PowerMaster. He said that would explain why the locomotive would sometimes shutdown on its own. Some of the older TMCC boards cannot handle more than 18 volts.

I reset voltage to 18 and the problem went away. This engine runs flawlessly now that track voltage has been lowered. 

I finally got around to taking a closer look at this problem. Reseating the boards and disabling Odyssey had no effect. I will start by replacing the R2LC board and see what that does.

Can anyone identify this little shrink-wrapped circuit I found wedged in next to the R2LC? I can't find it in any diagram that I have been able to get my hands on. There are two wires, black and yellow, coming from one end, and two wires, black and gray, protruding from the other end. There's a cap and possibly a diode or two - I didn't want to tear the shrink wrap so I did not get an unobstructed view. 

This little circuit gets really hot,  I mean to the point where the shrink wrap is real soft and you can't hold onto the thing. Whether this is an abnormal condition, I don't know. I'd like to understand what role this small circuit plays.

Thank you.

Len,

   That looks like a 5v DC power supply. I would say that or your DCDS is the problem.

Bill

That would fit the symptoms.  Either the reg going bad, or the DCDS or a load off it is going bad and drawing too much current.  The 5V regulator powers the DCDS vice the power supply from the R2LC for this model.  The 10 pin connector doesn't seem to have any wires for LED loads so maybe a bad DCDS.  G

Thanks everyone. I appreciate the guidance. That's the best part of this forum. I'll start with the regulator and DCDS and see where that takes me.