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MRC Booster Bad Function

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  • Member since
    May 2008
  • 30 posts
MRC Booster Bad Function
Posted by Fosc on Monday, September 14, 2020 10:07 AM

Good morning,

I have an issue in a portion of my layout( powered by Booster MRC 10(8) Amp).It is turned off, apparentely for no reason.
 
My layout is "E" shaped, measuring 9,7m x 1m in the both outer branches, and 7,5m x 1,1m in the central peninsula. It was connected to operate only by DCC and I use "MRC Prodigy Wireless DCC". This  model (3.5A) is  installed in the central branch and two Boosters( 8A) each in the external branches. These three branches are isolated from each other, following the recommendation of the MRC.
Now,  there is no tension in one branch extension fed by one of the boosters.
 
After I tested with a multimeter, the voltage in this problematic section is zero, while in the other branch it is 13.2V for the most part. That Booster flashes two green lights( "Power" and "Pilot") alternately. If I remove that one from the section and reinstall it on other branch it works perfectly fine.
 
Viewing this booster, its flash two green LEDs alternately. If I get off this booster from the problem section, and I install it in the other section, its go normally (power's green LED it stays lightining).
 
If I go out the booster that normal district (and that is working normally)and I install it in that other branch that is energy without, this flash alternately two green LEDs ("Power" and "Pilot"): power light/pilot turn off and power turn off/pilot turn on, and its stays this situation  indefinitely. However, it no have energy on the rails, measured with a multimeter.
 
But I don't understand the reason: If I turn off layout (the general DPDT switch) and I turn on then, the liquid crystal display of my cab (handheld) does not show short circuit —hypothesis that the internal protector in the booster was automatically activated and would cut the power to prevent  further damage resulting from a short circuit.
 
This is what is happening. That's why I suspect a short circuit. But where?
 
Before that, it worked well. Just install a crossover in the yard of that stretch to create a run around and the problem happened. Crossover removed, the problem remains.  And crossover reinstalled again, the problem remains.
 
Could someone help me, please? Thanks in advance for any help received. Fernando.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, September 14, 2020 10:20 AM

 What happens in the problem section if the booster is connected, but the track wires are disconnected from it? If it works normally without the flashing lights, it would indicate a short in that section. With the DCC stuff all turned off, set your meter on continuity, if it has that mode, and connect it to the track wires that would normally connect to the booster. If you get a beep or zero ohms, or whatever your particular meter does to indicate continuity (same as touching the probes together), then you definitely have a short somewhere.

 If no short, another thing to check is the rail gaps between sections. Did you use insulated joiners, or did you just cut through the rails? It's possible if you just cut through the rails that a gap has closed up, either through things shifting, or expansion/contraction. If it did, now the two sections are not properly isolated and that will cause problems when multiple boosters are used.

And then there is the not so obvious obvious thing - since you were working on the track with that crossover, is there a metal tool or track gauge sitting on the rails somewhere nearby that is causing the short? Wouldn't be the first person to leave something like a metal 3 point track gauge sitting somewhere and wondering why the system was showing a short.

                                           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May 2008
  • 30 posts
Posted by Fosc on Monday, September 14, 2020 5:35 PM
Good evening, Randy.  Thank you for the answer.

I didn't really understand what you said in §1 of your text. Wasn't there a mistake? although I do not have the complete MRC booster manual, I believe that the green "Power" LED is on and remains on without blinking, would this not indicate that the gadget is working properly? And if the two green LEDs flash alternately, this would not be an indication that there is a short circuit on the line, correct? Please clarify this question for me so that I can answer your other questions more clearly.
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, September 14, 2020 8:38 PM

 I don;t have the manual either, I'm going by what you say is happening. If the bad section has the flashing lights, I'm going to also guess this means a short.

 Since the problem stays with the track section when you switch the boosters around, the booster itself is not defective, it's the track.

 Another verification would be to disconnect the wires from the booster to the track in the problem section. If it stops flashing, that just verifies the issue is in that track section or its wiring.

 You can test for a short by putting your meter across the leads that connect to the booster. It should indicate an open circuit, not a short.

 Otherwise, look for the obvious (or not so obvious) - a metal tool across the rails where you were working, or the gaps that isolate this track section from the others closing up.

                                           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May 2008
  • 30 posts
Posted by Fosc on Wednesday, September 16, 2020 8:35 AM

Hi, Randy, good morning and thanks.

 

I have been following him on the forum for some time, and I admire him for his goodwill and consideration for those who need help and are within his reach. More than 28000 posts messages are not for anyone! And their responses always express their ideas about it with solid and pertinent arguments. With you, no simple posts like: "Yes, No, Maybe, It is possible, etc.

(So ​​I am here wondering where you find the time to give the most complete answers possible, and that is not at all easy. Hence my thanks and respect for always being willing to help anyone asking for help on the forum and, especially, the beginners like me).

My initial doubt arose from the use of the word without in the second sentence of the first paragraph; I would understand your explanation and would have no doubt if you were written with instead of without (confirmed in your second post); or adding a no in the following sentence of the same paragraph ... but move forward!

Completing my previous answer and answering your other questions:

1) Booster on, but with the wires that connect it to the rails off:

The "power" lights up the green LED and remains on without flashing.

2) Continuity test with the entire DCC system turned off:

    a) between the two wires that connect the booster to the rails: It didn't "beep", but it did indicate value (575);

   b) only one of the wires with their corresponding fitting on the booster (green socket): it did not "beep", but it marked infinite resistance (I);

   c) the other wire with its fitting on the booster: ditto 2), b) anterior;

3) With the main switch on, but the DCC switch off: the "power" light turns on normal and remains on without flashing;

- See results identical to a), b) and c) above;

4) With everything off in the model (both keys "Off"):

 - Results identical to 2) above.

Thank you. Fernando.
 

 

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, September 16, 2020 10:59 AM

 On number 2, getting a value of 575 on the meter - were there any locomotives or lighted cars on the track that those wires powers? If the track was emopty, I would expect an open circuit - you have 2 wires, which go to two rails, which shouldn't be connected by anything. But - 575 ohms isn't low enough to draw so much current that it would overload.

 However, since the booster lights up normally with the track wires disconnected, that tells us the problem is in the wires or tracks in the bad section. So now you need to carefully examine the wiring and the track for any place there might be a short, or a gap that has closed up. Turnouts are a good place to start.

                                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    May 2008
  • 30 posts
Posted by Fosc on Friday, September 18, 2020 6:38 AM
Good morning, Randy.
There was a short inside the old crossover that had been installed on the stretch, which was detected and resolved.
There were only cabooses lit in the lines, but no cars.
In addition, I replaced the wires that connected the booster to the rails, so that the problem of malfunctioning of this booster was solved.
Thank you very much for your explanations and your valuable assistance so that I could solve this distressing problem.
Fernando.

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