Atlas N-scale GP38-2 with factory installed decoder - problems

Model Railroader Electronics and DCC
1

I have bought a few monts ago an Atlas N-scale GP38-2 with factory installed decoder and I discovered that I couldn’t program the decoder. I tried both at home (with a Zephyr control station) and at the club (the New Jersey Model Railroad club in Union) with Digitrax PR3 and a laptop running DecoderPro. In both cases the decoder could not be read or written, neither in programming or operations modes. Eventually I replaced the factory-installed decoder with a Digitrax DN163A0 and I had no problems programming it. What kind of decoders are mounted on Atlas locomotives and is it worth buying locos with factory-installed decoders (Atlas or other brands)?

Nick

2

I have several decoders that exhibit the behavior you described. I put a 1k resistor across the rails of the program track and that fixed the problem. BTW, my decoders are all non-sound.

3

Atlas uses very low-end Lenz decoders with their pre-installed DCC locos. With the premium you pay for the decoder, you are not getting what you are paying for. Your best bet is to purchase the DC version and install an aftermarket decoder.

The Atlas decoders do not support speed tables or bemf. So, you will not be able to speed match them to any other loco.

Also, they lack CV read back. Personally, I never use the feature, but if you are trying to “see” or “read” a decoder with your DCC system, it wont.

To change the address with a voltage-limited programming track, you need to write CV17, CV18 THEN CV29…and you have to do it manually. If CV29 is programmed first, then the decoder will not accept CV17 and CV18.

David B

4

The Atlas decoders certainly do support speed tables. They do not support Vmid and Vmax, so you can not speed match them just by using Vstart, Vmid, and Vmax, but you can speed match them using the full 28 step speed table.

I have never had to maually program the three CV’s on my Atlas engines with factory equipped decoders. I do have to use the resistor across the rails trick, but I just use the regular 4 digit address programming routine of my Zephyr.

5

Well…I assumed the OP didnt know of this trick. Why dont you explain it to him? Without the resistor, you have to do as I have explained…wont work otherwise.

Personally, I have a SEB, so I dont have any programming issues.

David B

6

I solved the problem by replacing the factory-installed decoder with a Digitrax DN163A0. From now on I will stik to buying the locos and decoders separately…

Nick

7

I did not explain it because jeffrey-wimberly already had in the post before yours: