New to DCC and Befuddled

Discussion in 'DCC & Electronics' started by ScratchyAngel, May 8, 2008.

  1. ScratchyAngel

    ScratchyAngel Member

    So I grabbed a Prodigy Express a few weeks ago on eBay, and today my Atlas U25B came in the mail.

    I tested it out on a piece of flex track w/ye old DC transformer and she crawls beautifully.

    So, I figure I'll give setting up the Prodigy Express to the track a whirl, and see how it goes. As soon as I apply power to the track the lights come on and it makes a little hum. As I turn the throttle the pitch increases in steps: mmm-mmM-mMM-MMM, but not a budge in either direction.

    I switch the wires to Prog Track, select the prog track with the cab, and set the address to 0003, just in case, and set the start voltage to 001. Power down, reset the wires to be Main Track, same song, different verse.

    The loco says it comes with a DigiTrax DN146A decoder. I'm planning on replacing it with an MRC 1636 anyway, but I'm wondering what's actually going on, and if it indicates a problem with the Prodigy, with the decoder, or most likely of all is it PEBTAM (Problem Exists Between the Track and the Moron)?

    I wasn't prepared for buzz or hum with DCC, the loco is pretty quiet on DC, but if this is normal it really makes me want to go with the sound decoders.

    Any tips for the mentally impoverished here greatly appreciated.

  2. Nomad

    Nomad Active Member

    When a loco on dcc hum's like that, it usually means there is no decoder. First thing I would do is make sure there is a decoder in there.

  3. ScratchyAngel

    ScratchyAngel Member

    Ding ding ding.

    We have a winner, and a I'll be the loser. Yeah, the loco was cheap ($40), and I think put in the wrong box. The auction ad didn't mention DCC so I was pleasantly surprised.

    I've taken it apart now so I can swap out the frame for an Aztec frame, and there's a plain old PCB lightboard in there, despite the box. No loss, other than the shame of the thread, as I had planned on going the sound route (even bought the decoder already).

    Thanks Loren for the quick reply, and sorry for the quick post.


    P.S. FWIW, on the TrainWeb DCC installation site there is a note that the DN146A does sometimes have contact problems with the U25B, but no tell-tale hum.
  4. Nomad

    Nomad Active Member

    Glad I could help. After all the great help I have gotten on this forum, it is nice to be able to help someone in return.
  5. railwaybob

    railwaybob Member

    If it's an Atlas with the lightboard, Atlas and Digitrax both make a PC board equivalent that you can drop in to replace the lightboard. For install instructions, check out this page on my website.
    Atlas Decoder Install - Pg 1

    You can also install some headlights to replace the clear plastic diffuser.

    Bob M.
  6. ScratchyAngel

    ScratchyAngel Member

    Yeah, the MRC is near-drop in for the actual board (a few chips require a bit of filing, but it's the speaker for the sound that takes a bit more filing/milling than I'd care to try, so the $20 exchange at Aztec ought to work well for it. Hopefully I'll have the milled frame by next week. I'm sure one way or the other I'll start a thread about it.

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