Problems speed matching Atlas DCC eqipped locos

Model Railroader Electronics and DCC
1

I have been trying to modify the speed tables of two new Atlas N scale U23Bs which are DCC equipped and am having trouble. I have been modifying CVs 5 and 6 in order to set midrange and maximum voltage however this does not seem to be having any noticable effect on engine speed.

I am wondering if anyone knows who manufactures Atlas’s decoders and if the CV numbers are different on these decoders (I thought that these CVs were covered by the NRMA DCC standard and so should be the same for all decoders).

Has anyone had a similar problem?

This is my first experience with buying DCC equipped locos and I will admit that I am used to dealing with Digitrax decoders as I have installed a considerable number of these with excellent results.

I am running an NCE 5 amp system and have a sneaky feeling that the Atlas decoders are also by NCE.

On another note I have installed a couple of TCS CN GP decoders in some older Atlas locos which I picked up and have not been completely satisfied with the results. The engines run jerkily and are noisy as well. Any suggestions as to what I have done wrong? I have filed out a groove in the frames so that the moter feed wires are not compressed against the engine. Can the brushes end up missaligned inside the motor when they are re-inserted after soldering on the leads from the decoder?

I feel that there is something I am doing wrong as I have read very positive reviews of these decoders.

Any help would be appreciated

2

Simple, the bottom-end lenz decoders that Atlas uses do not have CV 5 or 6.

Cvs 5 and 6 are not covered in the NMRA DCC standards. In fact, only decoder compatibility is. CVs are recommendations.

Sucks, eh?

David B

3

In that case I think I’ll swap them out for Digitrax decoders and steer clear of Atlas DCC equipped offerings in the future.

Thanks for the info

4

That does suck. I thought Atlas was better than that. Is that also true for the HO “silver series” loco’s? I have a couple of the silver series GP40 which came decoder equipped.

5

Atlas has used a variety of decoders in DCC equipped locos over the years. Some of the older ones were low end Digitrax ones. Others are Lenz. It all depends on how old the loco is. There’s usualyl features missing from the decoders used in the factory-equipped models, either because the decoder predates the addition of some features (the really old ones with Digitrax decoders are liek this) or they simply eliminated features from the decoder to keep the cost down (mainly the newer ones). Bachmann is pretty much more of the same, DCC OnBoard (non sound) uses a really low end Lenz decoder, with less features than anythign Lenz sells themselves these days. For the HO models, a 100% improvement can be made by substituting a $12 NCE D13SRJ. For N scale a suitable board repalcement decoder should be available from at least one fo the major manufacturers, if not more

–Randy