Problem with Bachmann DCC Onboard loco and Digitrax DCS50 Controller

Model Railroader Electronics and DCC
1

Greetings! I am fairly new to model railroading and I apologize if this question has been asked before. Here’s what’s going on…

I added a Digitrax Zephyr Controller system to my small layout. I retrofitted a DC loco with a Digitrax controller and as one would expect, it works as expected. I then bought a Bachmann Spectrum loco with DCC Onboard. I can control it with the controller, but I can not change any of the CV’s or even the address. When I put it on the programming track, the controller returns a “d nd” message which means that it has detected an open circuit on the programming track and no current draw is detected.

A basic Digitrax decoder is actually pretty cheap so I will probably just end up pulling the Bachmann decoder unless one of you seasoned vets can help me troubleshoot my issue.

Thanks in advance!
Scott

2

I don’t know, I have not had any problems programming Bachmann DCC on Board locos with the Zephyr in either page or OPS mode, maybe try a reset on the main in OPS mode. The decoder is made for Bachmann by Lenz.

If you do change decoders make sure that all the capacitors are removed from the loco, some of them have the caps mounted on the board, and some have them mounted directly to the motor across the brush caps

3

If I recall, some of the Bachmann DCC on board locos used a version of the basic Lenz decoder. I have had the exact same d nd issue with these. From what I understand they don’t offer enough resistance so the Zephyr thinks that there is an open circuit. If you bridge the 2 program track rails with a 1K ohm resistor it will very likely work. This is what was suggested to me and I have since had no issues with these decoders.

4

Change the OPSSW #7 on your Digitrax Zephyr to C. This will enable the blast mode on the Zephyr. You’ll find " how too " in your Zephyr manual.

This OPSSW #7 is not documented in Digitrax book but it is mentionned on Digitrax and JMRI yahoo support forums. Other than that you may require a program track booster such as the PowerPax. I don’t use one on my Zephyr thow.

5

Thanks for the tip about the resistor… it did the trick!

Scott

6

[%-)] I know the decoder that came in my Bach GP35 is an NCE.(???)