Decoder installation ?

Discussion in 'DCC & Electronics' started by robgoo, Feb 13, 2006.

  1. robgoo

    robgoo New Member

    Trying to put some older MRC AD310 decoders into a couple of old Rivarossi steam engines. I hook up the orange and grey wires to the motor and the black and the red wires to the pick-ups. Im using a Prodigy Advanced system, and then I will program the engine but nothing seems to happen. Then when I put the engine on the main and it just takes off with no control over it. Am I not isolating the engine or wiring it wrong? With the other engines I have done(with different manufactures decoders) I could hear a faint buzzing noise coming through the decoder, but with the MRC decoders I get nothing. Any help would be much apperciated. Thanks, Rob.
  2. Russ Bellinis

    Russ Bellinis Active Member

    Are you isolating the motor from the chassis before you attempt to wire the decoders in? It sounds like the motor is picking up power directly from the rails and bypassing the decoder.
  3. robgoo

    robgoo New Member

    Russ, I actually removed the engine right from the chassie, but still left it wired up to see if that helped but the motor did nothing. When I take one of the other ad310 decoders I have and just touch the black and red wires to the track shouldn't I be able to hear it buzz or some indication of it being powered? Rob.
  4. Woodie

    Woodie Active Member

    This bit indicates to me (and I'm no expert) that you've wired it up correctly, if when you say you put it on the main, and it takes off (and the "main" is DCC and not DC).

    That tells me that the decoder has a speed step set in it from when it was used last. i.e. the loco that had the decoder in it was moving, and the loco either came off the track, or was taken off the track while running. It seems you may just have an addressing problem. If it's an older decoder, make sure you're setting it at the old "short address", and use that.

    That's just the first thing that I thought of. Maybe way off the mark, but. :wave:

    I've never heard any buzzing coming from any of my decoders. Albeit I only use 1 type. NCE D13SR decoders.
  5. robgoo

    robgoo New Member


    Thanks for the help. The manual says it is set up for 14 speed steps with the address of 3. So I should use this factoring setting? One thing, when I reinstalled the motor after isolating it, the decorder was buzzing and getting hot. I take it that it is not isolated. But i can not figure out why it is not isolated.

  6. jtloconut

    jtloconut Member

    Helo loconut here

    the screw that holds the motor to the frame may be the problem. If so black electrical tape a kadee plastic screw may do the trick.:thumb:
  7. Woodie

    Woodie Active Member

    Does the loco have a metal chassis? You will need to check if the chassis is "live", and supplying power direct to the motor. But as you say you put it in the DCC track (with decoder installed) and away it goes, the DCC track is AC power. Not DC, as the motor requires. Do you have a multimeter? (or just use an old 12 V globe). Touch the chassis, and either track. If the globe lights, then you've probably got a problem. But I doubt that will be it.

    Select loco address "3" from your DCC controller. Do NOT enter any leading zeros. Just "3". (by doing that on mine, it differentiates between long and short address when selecting the loco. Mine is NCE, though, and if I want a long address I must enter 0003). Remember, also, the "default" loco address in the decocder is 3. It may have been changed at some stage. So program the decoder with a short address of, say, 100, and use that. Use a full 3 digit address (no leading zero) so as to avoid any confusion. (but not greater than 127 of course). I don't know if the decoder you are having problems with supports long address or not.

    You will need to set your cab controller to 14 speed steps too, unless you program the decoder to 28 speed steps. However, I understand using 28 speed steps from your cab controller, on a 14 speed step decoder, produces a different problem from what you describe. It'll still go, but the headlight flashes on/off for each incremental speed step (or something like that), and the decoder still should respond to a speed step of 0. (i.e. bring the loco to a halt).

    Set the loco address etc on the programming track, of course. :)

    BTW........ you mentioned that it is and "older" decoder, and I'm assuming it has been used in another loco at some time in the past?
  8. robgoo

    robgoo New Member

    Actually there is no screw holding the motor in place. It just pushes down onto the gear for the wheeldrive.........That's when the decoder starts to buzz an get hot. Woodie, the decoders are brand new, but are the older models from MRC. Before I removed a piece of metal shapped like a fork it would run on the main DCC track with no control, but after removing it the engine will not do anything but like I said buzz and get hot. Thanks guys !!!!!!!!!!!
  9. Woodie

    Woodie Active Member

    Ahhhh... I'm not familiar with these Rivarrosi locos. What, and where was the "piece of metal shaped like a fork"?

    At this point, I would be removing the decoder from the loco, and hook it up directly to the track. (no motor), and a globe to the headlight function (blue & white wires for the front headlight), and at least get the headlight turning on and off. Then you know you've got the addressing right, and the decoder is in some sort of working order. Then ensure the chassis of the loco is not "live". I've found a multimeter to be one of the best bits of testing equipment I've got. They're relatively quite cheap, but extremely useful for this sorta thing.

    That's about all I can offer at this point. :wave:

Share This Page