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Locomotive Decoder Started Smoking! Help!!!

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  • Member since
    August 2014
  • 122 posts
Locomotive Decoder Started Smoking! Help!!!
Posted by KisNap on Monday, April 11, 2016 8:47 AM

Hi Everyone,
I installed a drop-in sound decoder board last night and when I put it on the track it began to smoke when I tried to get it to move!
The sounds and light all worked, but as soon as I give it a little throttle the decoder started smoking above where the motor contact is.  I ensured that the motor contacts weren't touching and I've installed one of these before and have done other installations of other decoders.  It even got so hot that the solder began to melt and became soldered onto the board.  Any advise would be greatly appreciated!

The N scale section of my website is now uploaded with a lot of various things.  Check it out: www.CarlettaTrains.com

  • Member since
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  • From: Phoenix, AZ
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Posted by woodone on Monday, April 11, 2016 9:15 AM

WE need more information- Like what kind of loco- Who's decoder??

  • Member since
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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Monday, April 11, 2016 9:17 AM

It sound to me like a defective decoder.

Did you try it on the programming track first?

It takes an iron man to play with a toy iron horse. 

  • Member since
    August 2014
  • 122 posts
Posted by KisNap on Monday, April 11, 2016 9:43 AM

The locomotive is an Atlas GP40 and the DCC sound board is an MRC 1812.  I don't have a programming track.  It was just on a piece of straight track separate from the layout, but not a programming track.

The N scale section of my website is now uploaded with a lot of various things.  Check it out: www.CarlettaTrains.com

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Monday, April 11, 2016 1:26 PM

KisNap

The locomotive is an Atlas GP40 and the DCC sound board is an MRC 1812.  I don't have a programming track.  It was just on a piece of straight track separate from the layout, but not a programming track.

 

A piece of straight track can be a program track if your system is in the program mode option. That option protects the decoder if miss wired or a short somewhere.

My NCE Power cab protected the Tsunami sound decoder in an install that I miss wired. The prcedure is in my manual. It should be in your manual.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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  • From: Reading, PA
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Posted by rrinker on Monday, April 11, 2016 5:05 PM

 For N scale, the tricky things are the motor tabs. I'm going to guess one of the motor tabs was touching the frame of the loco. Having the motor outputs connect to the track inputs (usually the frame of an N scale diesel) is instant smoke. This one looks a bit different, witht he motor wires INSIDE the frame - on the Kato ones, where the motor tabs come up over the outside, most decoders supply a piece of Kapton tape to insulate the frame at the point the tabs folder over it to go to the decoder. What you can do to keep it from happening is, with the decoder out, use a multimeter set on continuity. Measure between the motor tab and each half of the frame, and repeat for the other motor tab. At no point should there be any continuity. If there is, inspect to see if the motor has shifted or the tabs have gotten pushed down and bent to contact the frame. Do not install the decoder until there is no continuity between the frame and the motor tabs. Do NOT repeat the test after the decoder is installed. The ohms/continuity option on the meter applies voltage across the probes, and feeding power in the output of the decoder is a sure way to kill it.

 

                                --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
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  • From: Jacksonville, FL
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Posted by gatrhumpy on Tuesday, April 12, 2016 5:41 AM

You smoked the decoder and will have to get another one. Before you install another one, however, make sure the frame halves don't touch, and make sure the motor contacts don't touch the frame halves.

  • Member since
    December 2004
  • From: Bedford, MA, USA
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Posted by MisterBeasley on Tuesday, April 12, 2016 9:15 AM

If you're doing your own decoder installations, a programming track is essential.  It does some basic checking before it applies full power.  Most important, it makes sure the motor leads are properly connected to the motor.  This has saved me a few times.

I hate it when my Lenz throttle reports "Err 03," but then I remember that the programming track has just saved me the cost of a new decoder.

It takes an iron man to play with a toy iron horse. 

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