Help for a newbie

Discussion in 'DCC & Electronics' started by Crox, Jan 23, 2007.

  1. Crox

    Crox New Member

    :confused: I bought an Athearn DCC quick plug equipped GP35 (product 91763) and a Digitrax DH123P as advised by the shop. I removed the jumper board and plugged in the decoder to the nine pin connector as instructed in the Athearn instructions, on to programme track, programme address of loco (loco number) and nothing.....not a sausage.

    I have the MRC Prodigy Express and all my other DCC equipped locos have worked fine - this is my first attempt at installing a decoder myself. The decoder also came with a DHWHP harness that appears redundant with the quick plug equipped loco?

    I'm really new to all this DCC stuff so any help would be appreciated. I read another thread on here about a similar issue but didn't understand that.

    Thanks all
  2. Woodie

    Woodie Active Member

    The only thing I can think of, is to check that you have plugged it onto the loco the right way round. Ensure pin 1 is into socket 1 on the locomotive board. You may need a magnifying glass to check. The pin numbers should be printed in white little tiny numbers on the plug, and on the board.

    That's about all I can think of at the mo, without knowing more.
  3. UP SD40-2

    UP SD40-2 Senior Member

    Crox:wave:, i AM NOT familiar with the DH123P decoder:(, but i am familiar with the DH123:D. i know the Digitrax DH123 is TOO SMALL to fit the large 9pin socket that comes on the Athearn circuit boards:(. does the DH123P decoder fit in the socket properly? is it the same size as the socket in the circuit board? is the decoder upside down?(not installed properly). sorry to ask these questions:oops:, just want to cover these bases first;).
    did you try to run it first, before programing it?
    on the test/program track, does the address come up as 0003? it should.
    can you get a reading on the mainline? does the motor feel like its getting power?

    i AM VERY FAMILIAR with the prodigy express:thumb:,knowing the answers to these questions will help diagnose your problem;).
    :D -Deano
  4. Thoroughbreed

    Thoroughbreed Member

    Try putting the jumper back in and checking the engine on a DC track to verify functionality. I bought one and the driveshaft was disconnected on 1 side, and it ran very roughly, as it was dragging 1 truck around. Sometimes the wire to the motor itself isnt connected. Theres a single wire that connects to the motor on the bottom side, the board has the connector for the upper side of the motor riveted to the bottom of it.
    Just a few things to check out:thumb:
  5. Crox

    Crox New Member

    The DH123P instructions actually refers to just DH123 inside the packet. The nine pin decoder can only go in one way round due to the moulding - it fits just fine.

    I don't have a DC track but before installing the decoder I put the loco on the live DCC track the lights lit up and the motors were working.

    The decoder itself I've just put in where the jumper was - should I have used the harness and plugged that into the actual circuit board? Sorry to appear dense and I appreciate the help.
  6. Thoroughbreed

    Thoroughbreed Member

    The board doesnt have a real socket for the 8 pin connector, just a place for one. Sounds like the engine was fully functional before the addition of the decoder.
    The problem may be the decoder.
  7. Gary S.

    Gary S. Senior Member

    I have several Athearn "DCC Ready" locos and the Digitrax DH123 series decoders fit right in and worked perfectly. YOu shouldn't need any of the harness that came with the decoder. Can you get another decoder and see if the loco will work with it?
  8. Crox

    Crox New Member

    OK thanks - should I get the same decoder DH123P or should I try something else?
  9. Gary S.

    Gary S. Senior Member

    I would say buy whichever DH123 is cheapest, plug it in, and see if it works. Remember that the address will be 03 under factory default.
  10. MasonJar

    MasonJar It's not rocket surgery

    I have used this decoder in my Bachmann steamer, and I had to use the harness.

    It seems though, that the "Quick plug" has indeed rendered the harness (DHWHP) redundant. The quick plug is basically the harness built into the Athearn loco.

    I think that your problem is likely that the decoder is not seated properly in the "Quick Plug". I have had a heck of a time with a decoder or two trying to get it to snap right in. It required a considerable amount of force - and that's with the plug lined up properly, I might add...! ;):D

    It does not simply slide on - it must really *snap* in place. Once on, it will be quite difficult to remove. If you can plug and unplug it with relative ease, it's not installed properly.

    If you need a replacement for this type of "Quick PLug" equipped loco, it appears that the basic DH123P or DH123 would be suitable, as you do not need any harness from Digitrax to make it work.

    Hope that helps.

  11. Crox

    Crox New Member

    Thanks again guys. I took the decoder out - with a considerable amount of effort so it must have been seated correctly. I put it back in but still nothing so it looks like the decoder may be the problem.

    The Prodigy Express should simply programme this decoder right? Normally I've just put the loco on my programme track, programmed the loco number as the address and eveything has worked fine, I've not had to mess with CV's or anything. The Digitrax instructions only refer to programming with the Digitrax DCC kit. Of course the MRC instructions tell me to refer to the decoder instructions!:cry:
  12. Crox

    Crox New Member

    OK major embarrassment - left it all alone for a few days, going to take the decoder back to the shop but hey, why not check one final time. What's this? A loose wire? gulp! At least it'll teach me to be a little more methodical in working through problems and eliminating potential issues.

    Anyway, the way the Athearn runs now more than makes up for the few days of frustration and those CN Black and Orange colours look so cool hauling a train of tank cars.....

    thanks again


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