Decoder wire question.

Discussion in 'FAQs' started by DWP, Dec 30, 2004.

  1. DWP

    DWP Member

    This might be a simple question. I am wiring a DZ123 to a N Gauge
    Bachmann 060. I do not have any lights for it yet. What do I do with the blue wire? I hooked up the Grey and Orange to the motor and the Red and black to the track pick ups. The loco will not respond. There was something in the directions about checking the manual if not using lights but I cannot
    figure it out.
    Thank You Dave
  2. Gary Pfeil

    Gary Pfeil Active Member

    Someone will correct me if I'm wrong, but I've got several decoders wired with no lights and they work fine. The blue wire, as well as the yellow and white, are just cut and tucked out of the way. Check the decoder address and make sure it is what you've selected on the throttle. Maybe check with a volt meter that you've got power at the decoder black and red leads. My decoders , come to think of it, are DNs not DZs, but they ought to work in the same manner.
  3. Freelancer

    Freelancer Member

    The blue wire is the "common" (what that means, I don't know.) You connect your lights up to the yellow and white wires, and then connect them to either the blue wire, or connect it to the frame and ground them. I don't understand what exactly happens, but if you ground them then somewhere down the line it affects your system some how. Where as connecting them to the blue wire doesn't. If you are planning on adding lights, then I would definitely not cut those wires until you are ready to install the lights.

  4. DWP

    DWP Member

    I got it working. After checking everything with a meter and rechecking
    I realized that the engine had no weight. I pushed down with my finger and it ran! This was a new engine, I didn"t think to clean the wheels and contacts. Sometimes its the simple things that drive you nuts.
  5. sumpter250

    sumpter250 multiscale modelbuilder

    In DCC, the frame is either left rail, or right rail, but not "ground". The decoder uses a "floating ground".....the blue wire.
    Unused wires can either be clipped, or, if space permits, bound and stored for possible future use. They could also be "installed" for future use.
  6. Freelancer

    Freelancer Member

    DWP, glad to here that you got it working. That is probably the last thing you would have ever suspected.

    Pete, thanks for the correction, that is good to know. So what exactly is going on when you connect those wires back to the frame?

    Thanks, Freelancer
  7. 60103

    60103 Pooh Bah

    If you connect any of the output wires from the decoder back to the frame,
    and if the frame gets connected to the track power by any chance (either by being wired to a pickup or by contacting the track or touching another frame that is wired or ...)
    you have a fried decoder
    and get to try out the warranty.
  8. Gary Pfeil

    Gary Pfeil Active Member

    I don't remember the details so may get something wrong here. Some older locos have lights which only have one wire going to them, the other lead is the frame of the loco. If you don't wish to do the work needed to isolate the lamp from the chassis and use the white/yellow and blue leads as normal, you can use the frame connection as the ground instead of the blue wire. What you wind up with is (and this is what I don't remember the term for) half wave? At any rate, this will allow you to use the function to turn the light on and off, at the expense of the fact that if you run an analog loco, the headlight in your DCC loco wired this way will go bright and dim along with the throttle setting for the analog loco. This because the analog loco runs by the DCC system stretching the length of the duration of the time power is applied to one polarity or another. While this stretching won't affect the outputs of the decoders in you decoder equipped locos, it does affect that lamp which is connected directly to a rail. All this came from posts I've read at the Digitrax site years ago. The general consensus was it's not a great idea.

  9. Freelancer

    Freelancer Member

    Thanks guys, I knew that there was an after effect but I never quite understood what it was. I also thought that it was a much more severe problem. Anywho, thanks for explaining that to me.


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