Decoder compatability : LUSENET : Wiring for DCC : One Thread

I have a digitrax chief, and want to know if anyone has any experience using nce decoders, such as the one ttx sells for kato rs2, or the new lenz 103/105 decoders with a chief. are they truly compatible? or are there any "tricks" to programming them? I've had poor success with MRC AD310s with the chief(sold em on ebay after giving up on them), and also with older lenz decoders. thanx for any input.

-- Larry Keller (, May 02, 1999


I have used Lenz LE103FX /LE104FX decoders on Digitrax Chief and NCE systems with no problems. Some of the manufacturer's optional CV's are different than those in Digitrax decoders, but the documentation that comes with the decoder does an adequate job of explaining the details of each available CV. The differences among the different DCC systems is how communications occur between the CAB and Command Station. All signals emanating from the command station/booster to the tracks must conform to the NRMA standards. This signal is what all the decoders see. They are blind as to what is going on between the CAB and Command Station. Therefore, if the decoder is designed to recognize the standard NRMA signal and the mandatory CV's are supported per NRMA standards/RP's, the decoder will work on any DCC system that complies with the NMRA standards.

-- John Draper (, May 12, 1999.

I use a System One and found that the MRC decoders can only be programmed using registers (I believe Larry talked about is in Model Railroading).

-- Nelson Allison (, October 20, 1999.


The MRC decoders only support register mode programming, which the Chief will do fine, but needs to be set to register mode programming before it will do it. Also the MRC decoders only support 14/28 speed step mode and short 2 digit addressing. As long as these limits are known, and the Chief set to properly compensate they will work fine.

As far as the NCE decoder [TTX RS2], they should work just fine, have not heard of any problems here.

The Lenz xf decoders heres is a list of issues on them: The power station continuously detects a short and shuts down any time the decoder is present (seen on NCE Power House Pro layouts with 12 gauge wiring) A total lack of control of the decoder (seen on one CVP Easy DCC layout) The locomotive unexpectantly begins moving at full speed without any user control (seen on a few Digitrax and CVP systems)

But also note: If you have experienced one of these problems, or if you are concerned that you might experience the problem in the future, the solution is to either place a filter on the power station (free of charge from NCE for their systems) or to install an additional small capacitor on the decoder. This is provided at no cost as part of our warranty service. All XF decoders shipped since June 1999 have this capacitor installed to avoid the problem completely.

Also: When user defined speed tables are used in 128 speed step mode on Digitrax systems, the value contained in CV67 is used in calculaating speed step averaging. If this value is set too high the locomotive may move slightly when the throttle is set to stop. Setting a value of 0 in CV67 solves this problem.


Remember Always Have Fun and Enjoy!, Don Crano Akron, Oh NMRA #096211 Visit Model Railroading with DCC at:

-- Don Crano (, October 21, 1999.

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