MU linking backwards?

Pastor John Jul 4, 2020

  1. Pastor John

    Pastor John TrainBoard Member

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    I am returning to model railroading after a decades long absence. I am a total DCC noob. So, last month I bought a used Digitrax DCS50 Zephyr controller on the Trainboard Swapmeet and last week I bought two Walthers blue box DCC equipped F units on eBay that arrived a few days ago.

    Today, I set up my newly constructed, 3 foot long, test track, hooked up the DCS50, and attempted to operate the engines and work through some of basic operations.

    Everything worked.

    Sort of.

    Both engines answered to their addresses and ran acceptably well. Sure, blue box engines are far from "high end" but they're miles ahead of the department store Tyco and Bachmann engines I had in high school.

    But, when I tried to slave them (MU) together, I followed the directions that said I should make sure the two units were running in the same direction. They were. But, when I MU'd them together, the 'B' unit changed directions and now ran the opposite direction of the 'A' unit.

    So, since I am total noob, what just happened? Is this normal for Digitrax? Normal for this controller? Is the controller acting screwey? Is the B unit DCC conversion somehow wired wrong?

    Any help is appreciated.

    Sent from my moto g(7) play using Tapatalk
     
  2. dualgauge

    dualgauge TrainBoard Member

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    Try turning the B unit around. The decoder might be programed for the other end to be the front. Have seen that happen before. Hope that works for you.
     
  3. Pastor John

    Pastor John TrainBoard Member

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    I can make it work like that, the problem is that what the B-unit thinks is "forward" changes (flips) from when it is operating independently and when it is slaved to the A-unit. That seems odd, but I have no other references with which to compare it. That can't be normal, can it?

    Sent from my moto g(7) play using Tapatalk
     
  4. CSX Robert

    CSX Robert TrainBoard Member

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    No, that is not normal, sometimes you do want the mu'ed locomotive to flip its forward direction of travel, like when mu'ing two loco's back to back, but of course not always. The Zephyr is supposed to use the loco's last direction of travel as it's normal direction of travel when placed in a mu. For example, if you back loco 2 up to loco 1, then mu loco 2 to loco 1, the Zephyr should place loco 2 in the mu with its normal direction of travel as reverse so that when you run the consist in forward that loco will run in reverse. What I have found, however, is that sometimes this just does not work right with my Zephyr. It will get to where no matter what I do it will not place loco's in the mu in the right direction, but if I do the option switch 36 reset it will go back to working correctly.
     
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  5. rray

    rray Staff Member

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    It could be that the motor wires (orange gray) are wired backwards on that loco, and the direction of travel CV is set to reverse to compensate. When you MU, you have to also assign the direction of travel as reverse for that loco.
     
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  6. Pastor John

    Pastor John TrainBoard Member

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    Thank you everyone. I didn't think that it was normal, but since I only have the two DCC engines that I just bought, I didn't have much to compare it to. Now I know that I can make it work, and look for possible solutions in the longer-term.

    Next, repair all of the couplers...
     
  7. Pastor John

    Pastor John TrainBoard Member

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    For what it's worth, I revisited this experiment this week and, I think, the problem was that I might have missed a step, or did one step incorrectly, the first time. When I repeated this experiment, this time everything worked correctly. Yay! I'm still going to proceed cautiously until I gain a bit more experience and proficiency. There is much to learn. That said, one of the next things on the list is to convert an Athern Blue Box F-unit to DCC so that it can run with the other two. There's another step after that, but again, I know that I need to build up some experience, proficiency and self-confidence before I invest more money and bite off too much at once.

    Again, thank you everyone.
     
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  8. Keith Ledbetter

    Keith Ledbetter TrainBoard Member

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    Great to hear. Always a good outcome when. Nothing requires surgery or major resets
     
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  9. Massey

    Massey TrainBoard Member

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    I did this a few times. It isn't hard but I would highly recommend soldering everything over the clips that Digitrax and others give to make the installation in BB locos easier. The motor clips are OK but the clips to pick up current from the frame and trucks are not great. Neither are the clips for the cab light. I simply soldered all the wires to where they needed to be and the problems I had were solved. An Atlas or Athearn Dcc Ready loco would be a much simpler install and those locos always ran well for me. My favorite locos were always my Katos and they usually required a decoder with a 8 pin plug to add DCC. Plug and play in most cases.
     
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