Image above captured on the upper deck of the layout where scenery has progressed to some extent...
Shot with Olympus C-750

Welcome to the SP Oregon Division!

An N Scale RR depicting the good old days along "The Friendly".

Sunday, June 16, 2013

Digitrax Sound Decoders with Stalling Issue?

Trying to troubleshoot what is taking place with a couple locos I have on the layout that are equipped with Digitrax sound decoders..Here is a vid I took last night showing what I am combating here:

These chassis are both N Atlas SD9's MUed together via jumpers in an effort to diagnose why the sound decoders (SDN144AO) fail even with a combined 12 axles for electrical pick-up. Are these sound decoder boards in need of replacement?  I have a number of these decoders in use on the layout (in various locomotives), and none exhibit the same characteristics as these latest two that I purchased together.  They worked fine for a few opp sessions and now are both completely useless running solo, stalling every one to two feet on clean track with clean wheels.One would assume that both units would stall at the same time since electrically MUed, but obviously not the case. Watching the vid one can see the headlight drop out as well as sound reset when locos stall.  We have tried wiggling the decoder boards to check for loose fit while MUed, but there is No evidence of that being a possible cause for decoder dropping out. Of note is that SD9's with conventional non sound decoders (DN163AO) perform flawlessly through this track section even when running solo (as well as above mentioned other units using this same SDN144IO decoder operate fine)....
I will contact Digitrax and see what their recommendation is next.  I am thinking something is internally wrong with one of the components on the board regarding this particular run of decoders that I purchased together.
Anyone else seen this, have ideas / feedback?
Ya I know the sound file is in need of help, but that will follow...


  1. I'm not familiar with Atlas' N scale units, but the HO scale units use a small metal clip to connect the track power wires to the trucks. These clips aren't reliable enough for sound equipped units. I've replaced every one of them by soldering the wires directly to the brass pieces that fit in the trucks on my units. Along with making sure all of the units have capacitors, this has fixed all the stalling problems I had. Hope this helps.

    Tom Patterson

  2. Thanks Tom.
    Digitrax said similar,
    Sound decoders are much more sensitive to electrical flaws. They require more current, and interruptions are amplified by loss of sound. They offered me to return under warranty if needed.
    More keep-alive is a great idea for any sound decoder, but cap technology is lagging for us N-scalers. I appreciate the feedback.

  3. same problem on my atlas gp 38 digitrax tech said to make back emf cv57 a low value ie 1 range is 0 to 5 and lower the main volume cv58 ie 8 range is 0 to15 then bell volume cv141 can be adjusted range is 0 to 64 and horn volume cv142 can be adjusted. this has helped but try to consist with a non sound loco !!! !!! I agree this is a real problem