A Mind Of It's Own

Discussion in 'DCC & Electronics' started by Woodie, Dec 18, 2005.

  1. Woodie

    Woodie Active Member


    I wired up my first decoder last night (NCE D13SR just wires, no plug) and on DC it seems to have a mind of it's own. It runs fine, and speeds up, and slows down, and stops, and starts, just like regular DC, however, every now and then it just flips into reverse, and TOOT.... off the loco goes in the opposite direction, as the same speed as forward). It appears to do this randomly, and at no specific points on the layout. Taking the DC controller back to stopped, and then moving it off again (same direction as far as the controller is concerned), and the loco will then go in the direction it is supposed to. I never really left it long enough (after it auto-reversed) to see if it would auto-change-direction again. It would do this once every 4 - 6 circuits of the layout, and randon spots around the layout.

    Any ideas? :confused: :confused:

    Can't answer how it runs on DCC, cause my new DCC power supply (when I opened the box last night) don't have any power come out of it. Gotta return it.
  2. MasonJar

    MasonJar It's not rocket surgery


    Are you running "smooth" DC power? If you have a powerpack that supplies "pulsed" DC, it can confuse the decoder.

    The other thing I would check, but which might be hard if you can't use your DCC controller, is if the decoder is in fact set to run on DC. There is a CV (which one escapes me right now) that must be set for DC running (at least on the Digitrax decoder I have in my Bachmann 4-6-0). Soundtraxx sound decoders cannot be run on DC.

    Hope that helps.

  3. Woodie

    Woodie Active Member


    The DC controller is smooth (i.e. not pulsed), and the decoder defaults to DC=YES. It's an old Lima, (pancake motor) that is not too good on the track pickup. It's not all wheel pickup. Out of the 12 wheels, it only picks up from two at the front, and two at the rear. It's my "do it to it first before doing it to the good ones" loco. I'd assume everyone has one of those!!

    Currently, I'm blaming it on the dodgy pickup. Dunno if that's correct, though.
  4. 60103

    60103 Pooh Bah

    One thing you'll notice in DCC is sensitivity to dirty track. It may take you a while to get a track cleaner that works -- everyone has a different idea. (I use Aero locomotive works.) I think that slightly dirty track may cause the signals to be corrupted.
  5. Woodie

    Woodie Active Member


    I try to keep the track reasonably clean. The black gunk that comes off it sometimes!! :eek: :eek:

    I decoderized another loco with all wheel pickup and it doesn't do what the other "dodgy pickup" one does. Runs nice and smooth and consistent.

    It's pretty easy to tell when it's a dodgy pickup, especially if you've got the headlight on. Somtimes you'd think you'd had the headlight set to "firebox flicker"!!! :eek: This loco wasn't the best of runners on DC either.

    It was the automatic shunting itself off in reverse that I was concerned about.
  6. MasonJar

    MasonJar It's not rocket surgery

    Is there some sort of short inside the loco that would allow it to "swap" the wires running to the motor? So that the power is reversed, even though the decoder did not change the power?

    If you really want to know if it is the decoder, I suppose you could install a different one, and test the original in some other engine.

  7. capt_turk

    capt_turk Member

    Alot of the random directional changes are caused by RF interference. Make sure the wires going to the track are twisted. This tends to cancel out the interference.

Share This Page