short on line

Discussion in 'Getting Started' started by joefryfry, Jan 29, 2008.

  1. joefryfry

    joefryfry joefryfry

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    imgsrc="http://www.bluemountainaerialmapping.com/track.JPG"

    The gaps are the red lines. I am using MRC Prodigy Express and MRC reversing units. I get a short or "svda" on my menu on the cab when the engine passes over one of the gaps. It happens in each loop. I have tested it running just one engine with no cars with the same result. I believe I have the reversing units wired good. Let's go from there...any thoughts? Thanks. RL = reverse loop. The rest of the track is wired common rail.
  2. joefryfry

    joefryfry joefryfry

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    A guy at MRC says I need software upgraded in my base unit and a bigger output power supply. Does this sound like a bunch of hooey, or about right?
  3. Nomad

    Nomad Active Member

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    The tracks that you gapped don't look like reverser's to me.

    Loren
  4. Squidbait

    Squidbait Recovering ALCO-holic

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    Not entirely. There's an issue with the earlier releases of the Prodigy systems... they'll get a short, go into SVDA, and the loco will carry on merrily, ignoring what you tell it.
  5. Squidbait

    Squidbait Recovering ALCO-holic

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    I also think you need to put in more gaps, and perhaps another reversing unit. If I'm reading it right, you have 4 reverse-loops, and each will need a reverse unit.

    Just for trouble-shootings sake, I'd put a gap each leg of the turnouts (not the point end, just the two diverging routes).

    Also, does it happen when you only have 1 loco on the layout?
  6. joefryfry

    joefryfry joefryfry

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    They are more like a wye, but as far as I can tell they are reverse loops, they just don't look like a loop. The tracks come back on themselves. The main line would be the figure 8.
  7. joefryfry

    joefryfry joefryfry

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    No there are two reverse sections, the red lines are the insulated gaps. The result is the same whether I have two locos, with or with out cars. My cars have metal wheels, but everything runs well with those. The short happens when the engine hits the track on the other side of the gap. When the short happens, the train just keeps chugging doing what is is doing, I unplug the cab, plug it back in, and get control of the train again.

    By the way, the crossing on the figure 8 is a bridge, not a cross over. THanks.
  8. Squidbait

    Squidbait Recovering ALCO-holic

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    Then your gaps are likely in the wrong place. You need to isolate the sections that are common to all 4 reverse routes. That means you need to put gaps at the point ends of all the turnouts.
  9. Squidbait

    Squidbait Recovering ALCO-holic

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    I still think you need a 3rd reverser on the crossover section in the middle.
  10. joefryfry

    joefryfry joefryfry

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    Just to update, nothing was wrong with the layout or wiring or gapping. The base unit got a software upgrade and they gave me a stronger power pack for $25. Not getting any shorts now. Just info for MRC DCC users
  11. Squidbait

    Squidbait Recovering ALCO-holic

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    Ah. I'd heard the early Prodigy Express units were a mite touchy and a little too quick to shut down with the SVDA screen.

    Glad you got it sorted out.
  12. Nomad

    Nomad Active Member

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    Great news Joe. Is this the first time your layout is operational?

    Loren
  13. joefryfry

    joefryfry joefryfry

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    Not really. I had just designed and built this layout after a tremendous amount of thought and planning. It is my first time with DCC and everything worked fine except for the lack of power to control the reversing units. It works great now. Now I have another problem. My locos wheels seem to be slipping quite a bit. I have searched for solutions, briefly. I was needing any advice people could give for traction, other than replacing the wheels. Thoughts? I am going to start a new thread on this also. Thanks.