# Lurching Piko Mogul on DCC



## gdtmsailor (Apr 17, 2020)

So I have a Piko Mogul that I just tried to run on DCC and it has an issue where it is often lurching rather than running smoothly. I thought maybe the issue was track, and track connection, but when run on analogue all is okay. Is it possible that something is wrong with the decoder?


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## Greg Elmassian (Jan 3, 2008)

maybe BEMF settings...


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## gdtmsailor (Apr 17, 2020)

Oh - that's a good idea. Would you turn BEMF off entirely. For the Soundtraxx decoder that would be CV10 to 0?


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## Cougar Rock Rail (Jan 2, 2008)

I’ve seen a friends new loco do this exact thing on my layout, which is DCC, and it turned out the decoder couldn’t handle my track voltage of about 22.5V. Once I limited the output via the central station it worked fine. It seems the decoders just aren’t made to handle higher G scale voltage like they are supposed to.


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## gdtmsailor (Apr 17, 2020)

Oh no way - wow that's bizarre. I'll give that a try!


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## 1to3 (Mar 15, 2017)

Piko would ask you what power supply and throttle you are using. Soundtraxx decoders need clean power, so too much voltage (over 22V/24V max) would be an issue as well as brand of power. NMRA standards say 24V, but nearly all 24V power systems send more than that to the track when waves are calculated, so you likely want 22V or a little less. Piko might actually be the only manufacturer that actually follows NMRA exactly, so most folks blame them - even though "NMRA standards" are supposed to be standard.  

My Piko mogul would flash lights when power was too high. Once I used a "NMRA standard" transformer it was all good. I think Piko uses a 20V/6A power supply on their digital system.


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## Dan Pierce (Jan 2, 2008)

Largescale NMRA standards are not what I would expect. DC voltage at 27 volts, but DCC at 22 volts. Since DCC is a square wave, 22 volts after a bridge rectifier is less than 22 volts!!! I have an old Zimo system that has 25 volts DCC on the output (my command station has 24 volts AC input) and LGB, Massoth, Zimo decoders all work great. MRC decoders do not like my system, I have to add heat sinks to the 12 volt regulator as it gets real hot. Some Soundtraxx decoders go to voltage fault. 

I have found US companies building systejms stay at or below 21 volts but European systems go over 22 volts.


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## gdtmsailor (Apr 17, 2020)

You are all right! I switched down to the 20V/6A power supply and no more issues!


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## Cougar Rock Rail (Jan 2, 2008)

gdtmsailor said:


> You are all right! I switched down to the 20V/6A power supply and no more issues!


That’s great news—thanks for letting us know!


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## Greg Elmassian (Jan 3, 2008)

So what power supply were you using before?


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## phils2um (Jan 11, 2020)

I'm surprised. I would have expected Piko to source more robust decoders for their G gauge trains.

Phil S.


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## Greg Elmassian (Jan 3, 2008)

I believe he said his problem was solved with a better power supply


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