# puzzling decoder question



## lownote (Jan 3, 2008)

I've been enjoying the NCE DCC system, and now I've got 7 locos running under DCC. But I have an odd issue. Some of the decoders run at 128 speed steps, and some at 28. That is, with some of the locos, the throttle registers the top speed as "128," while with others, it registers the top speed as "28."The NCE manual suggests that if the decoder is capable of 128, it will default to 128. When I was running under Airwire, they all operated at 128 steps once I told the throttle. 


Not sure why this should be, and I cant figure out how to change it. 28 would be fine--with a lot of momentum programmed in, it does not matter that much. I'm just not sure what parameter to adust to get all decoders on the same page

Thanks!


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## George Schreyer (Jan 16, 2009)

which ones report 28 speed steps? A command station can be programmed to send a certain format to a certain address. Are you sure that you haven't told it to run those decoders in 28 step mode?


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## lownote (Jan 3, 2008)

Thanks George

It seems to be random--these are all QSI decoders, all "magnum" or aristo. Three report 128, the rest 28. The NCE throttle allows you to choose either 28 or 14, and the manual says it will default to 128 is the decoder is capable of it. It's normally not a problem, but today i tried to form a consist, and couldn't do speed matching with one at 128 and one at 28


i have no idea why this should be happening


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## George Schreyer (Jan 16, 2009)

hmm... I have only 3 QSI decoders, but they all default to 128 steps on my Digitrax system.


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## lownote (Jan 3, 2008)

Oddly, most of mine are defaulting to 28. I guess I may need to call NCE. I looked at the manual a little and could not find anything


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## Greg Elmassian (Jan 3, 2008)

Hmm... the decoder CV 29 has a bit to set 14 or 28/128... there is no separate 128 setting. 

The decoder decides what mode to operate depending on whether it receives a 28 step command or 128 step command. 

Try cycling the 28/128 button on your throttle... 

Regards, Greg


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## lownote (Jan 3, 2008)

Greg

What button is that? I was not able to find it in the manual


WAIT! I just found it. I'll try it tomorrow if it's not raining 


And thank you very much!


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## Greg Elmassian (Jan 3, 2008)

We're here to help! 

Let us know.... 

you might have to change to 28... hit a couple of speed steps, then hit 128... the throttle should tell you what it's doing on the screen.. 

Greg


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## aceinspp (Jan 2, 2008)

Just go to the button and change it from 28 to 128. This is easy. later RJD


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