New to DCC decoder installation????

Dave Howie Feb 13, 2018 at 1:32 PM

  1. Dave Howie

    Dave Howie New Member

    I was old school DC way way back. Just started up again and going all DCC in N scale. Are there sites that give step by step decoder installation. I tried last night to install a decoder in an Atlas GP 38. Got every thing installed but the loco will not respond at all. No lights no movement. Any suggestions welcome
  2. SP-Wolf

    SP-Wolf TrainBoard Member

  3. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

    Rule 0 of DCC decoder installs: KAPTON TAPE IS YOUR FRIEND. Literally, the only thing you want touching the frame or strips are the rail power pick-up wires (or pads) of the decoder.

    The TCS installation pictures are some of the best out there. Also, Spookshow's database has some good photos of loco innards, even if not specific instructions. Also, use the search function here on TB; there are lots and lots of old threads where folks post photos of their installs.

    You don't say which decoder, so difficult to give guidance on what to look for at this point.
  4. woodone

    woodone TrainBoard Member

    There are several things that can go wrong with Atlas N scale DCC installs. First is the way most decoders make the decoder to motor contacts. The two motor tabs just stick up an make (you hope) with the decoder. Second is the thickness of the decoder. Where the decoder fits into the slots of frame the decoder is not thick enough to make contact.
    Put a small dab of solder on each tap where it slides into the frame. This will make the taps a bit thicker and now will make contact with the frame. For the motor will depend on who’s decoder you are using. I solder a short jumper wire from the motor to the decoder.
  5. wombat457

    wombat457 TrainBoard Member

    I am with others, TCS Decoders are the way to go and come with very clear easy to follow step by step instructions. I was like you and very apprehensive about doing decoder installs until I started using TCS decoders.

    What might help people to work out your problem though is what type/make of decoder did you use?
  6. jdcolombo

    jdcolombo TrainBoard Member

    If you are installing a board-type decoder (rather than a hard-wired decoder), the usual culprit if the engine is not responding at all is the contact between the decoder and the frame "fingers" that are supposed to contact the power pickup pads on the decoder. As someone else has already pointed out, you can cure contact problems by putting a thin coat of solder on the pads until the decoder is "tight" under the frame fingers. if the pickup pads are only on one side (top), you can also try using some .010 sheet styrene underneath to tighten things.

    If the decoder responds (e.g., headlight comes on) but the engine won't move, the usual culprit is the contact between the motor pickup strips in the center of the frame and the motor supply pads on the bottom of the decoder. You can try to bend the decoder pickup strips upward to put more pressure between the strips and decoder (and make sure that the ends of the strips are actually contacting the pads and aren't skewed off them). A better solution is to hard-wire the pads to the strips, but this makes for a more difficult installation.

    If you don't have an electrical multimeter, get one, and make sure that it has a continuity check setting. You can use the continuity check to make sure power gets from the rail through the wheels, through the frame to the decoder and also to make sure that nothing is shorting from one side of the frame to the other or from the frame to the decoder. You can get a perfectly useful multimeter for $25 or less from places like Lowe's or Home Depot.

    While the theory of "drop-in" decoders is great (easy installation), the practice is much more variable. The drop-ins often aren't as easy to install as you might believe (e.g., the frame halves need to be separated to take out the old light board and slip in the decoder) and they often need tweaks as outlined above to work. And then even after all this, they will one day mysteriously stop working and need additional tweaks. I've found that by the time I'm done with the installation process and these tweaks, I could have hard-wired a small motor decoder like an ESU LokPilot V.4 (my favorite) or a Digitrax DZ series or a TCS M or Z2. If the engine already has a light board, I use the factory board for power-pickup for the hard-wired decoder and also re-use the LEDs by cutting the board traces and then wiring the decoder's headlight and rear-light function wires to the now-cut LED circuits. And the advantage of hard-wiring is that you know everything has a solid electrical connection . . . forever.

    John C.
  7. hoyden

    hoyden TrainBoard Supporter

    John C., thanks for those observations; drop-in vs wired. After installing many drop-in decoders over the years I am having to work through the problems you enumerate.

    Also, I never put a newly installed decoder locomotive on the main track right off. The new installation goes on the programming track first. I won't put it on the main until it passes the programming track.

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