MRC Reverse Module indicates shorts : LUSENET : Wiring for DCC : One Thread

I am getting shorts when I hook up MRC Reverse Loop Module

I'm laying out an HO scale, basic dogbone with 2 reverse loops, in a 2-level layout. I'm currently finished laying track and the wiring (for DCC operation) for the lower level. The DCC unit (an Intellibox) and the power source haven't been hooked up yet.

Here is my problem:

So far, the tracks do not indicate any shorts by themselves, however, when I hook up the Reverse Loop Module (MRC unit), I'm getting "shorts" all over the tracks using the Short Detection device described by Mr. Gartner. The shorts are everywhere, i.e., between the two rails (anywhere on the tracks) and also, across the insulated gaps between the regular and the reverse loop. When I disconnect the MRC module, the shorts go away!

The model shop here told me that: "I was measuring the DC current, whereas the module is set to work with AC current and this was normal". When I've called MRC, they did not provide any clear answer either.

Is this normal? Or is there a fault/problem with the Reverse Loop Module and it needs to be exchanged?

Thank you sincerely for any help or assistance you can provide.

Ali M. Berke

-- Ali Berke (, November 13, 2000


After re-reading your question a few times (and finding a picture of the reverse loop controller on the Walthers site) I am going to make the assumptiion that:

- you have connected one pair of wires to the main track of your layout and the other pair of wires to the track in the reverse loop.

If that assumption is correct then based on my guess as to the circuitry in the module, I think that what you are seeing is what you should expect. In normal operation the module will draw power from the rails to operate. Since the short detection device that Allan describes does not take much power to operate, it will detect a short when you have the module connected to the track.

I don't think the module is defective. I suggest you not connect it until you are ready to run trains. In fact, I suggest that you connect your command station to the main part of your track and make sure you can run an engine on it. Then connect the reverse loop controller and try to again run on just the main part. If that is OK then run the engine into the reverse loop and see if it is OK. By doing this in stages, you can easily decide where the problem is because you know the last thing you did before encountering a failure.

Hope this helps.

Dale Gloer

-- Dale Gloer (, November 17, 2000.

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