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New to DCC, Digitrax/Athearn Decoder issue

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  • Member since
    February 2011
  • 8 posts
New to DCC, Digitrax/Athearn Decoder issue
Posted by Rockit75 on Wednesday, October 19, 2011 3:57 PM

Hello, I just switched from DC to DCC but am still new to the hobby.  I purchased a Digitrax Zephyr hooked it up and tested a DC loco on it under channel 00 and it worked fine.  I alos purchased a Digitrax DHAT wire harness to convert my Athearn Flywheel Drive DC loco to DCC.  I installed this according to the instructions.  I then installed a Digitrax SDH164D decoder with sound.  Everything looked good tried it on the track under channel 03.  The sound and lights worked fine, the but the loco did not move.  I took it all apart, reassembled double checking all electrical and mechanical and again lights and sound worked, but no movement. 

Not sure if I am missing something obvious as this is my first DCC experience... the only thing I'm thinking now is that maybe my Athearn loco is older than what the harness was designed for... I checked the Athearn site and they don't sell my DC loco anymore which makes me wonder. 

Any suggestions?  Thought I would check here before returning to the store.

Chad

  • Member since
    August 2006
  • From: Greendale, WI
  • 108 posts
Posted by Robert Frey on Wednesday, October 19, 2011 5:49 PM

All DCC decoders must be insulated from the frame. The Athearn motor lead is connected to the frame under the motor. Did you insulate it?

Bob 

Website: http://bobfrey.auclair.com

  • Member since
    February 2011
  • 8 posts
Posted by Rockit75 on Thursday, October 20, 2011 8:54 AM

Thanks for your response.  Well their was a brass clip on the bottom of the motor with two flanged pieces that made contact with a silver metallic plate on the frame.  The Digitrax DHAT wire harness replaces this brass clip with one that does not have the flanges and has a wire soldered to the end of it.  I assumed this new clip separated any motor contact with the frame. 

However if I messed this up and the contact was still being made shouldn't the train still run in DC mode?  Maybe I will remove the motor and try put a pieces of non conductive material over the silver metallic plate and see what happens. 

Any other suggestions?

  • Member since
    February 2008
  • 8,878 posts
Posted by maxman on Thursday, October 20, 2011 11:33 AM

Rockit75

Thanks for your response.  Well their was a brass clip on the bottom of the motor with two flanged pieces that made contact with a silver metallic plate on the frame.  The Digitrax DHAT wire harness replaces this brass clip with one that does not have the flanges and has a wire soldered to the end of it.  I assumed this new clip separated any motor contact with the frame. 

However if I messed this up and the contact was still being made shouldn't the train still run in DC mode?  Maybe I will remove the motor and try put a pieces of non conductive material over the silver metallic plate and see what happens. 

Any other suggestions?

If that bottom plate touched the metal frame at all you've got a short and probably fried the decoder.  It is recommended that you put some insulation tape between the motor bottom and the frame.

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, October 20, 2011 1:44 PM

 For future reference, before testing the loco on the main track, try it on the program track. Try to read the address (a new decoder should be 03), and try programmign something, like setting the address to the cab number. If and only if this works, then try it on the main. If there is a wiring error such as a short of the motor terminal contacting the hot frame, the programmign will fail, but the power ont he program track is low enough that the decoder won;t fry. If it won;t program, check carefully for wiring problems. Follow this simple rule and you should never fry a decoder from an installation error. Not all systems have a low power program track, but the Zephyr definitely does.

                        --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
    July 2006
  • From: Pittsburgh, PA
  • 1,796 posts
Posted by JoeinPA on Thursday, October 20, 2011 2:44 PM

I would also add that before you try a decoder install you should see if you can find a tutorial on a decoder install in the loco or one closely related.  TCS and others have a very good representation of decoder installs on their websites.

Joe

  • Member since
    December 2001
  • 1,932 posts
Posted by Stevert on Thursday, October 20, 2011 3:00 PM

Did the lights blink when you first applied power after you first installed the decoder?  If they did, and you left it on the powered track and tried to run it, then yes you probably blew the motor circuit.  More info here:

http://kb.digitrax.com/index.php?a=81

But if that's the case, Digitrax will repair/replace it.  They have a one-year "No Worries Warranty".

Edited to add that when you replace it, be sure to follow the excellent advice already given to insulate the brushes and test it on a programming track.

  • Member since
    February 2011
  • 8 posts
Posted by Rockit75 on Thursday, October 20, 2011 11:13 PM

Problem Solved.  Thanks for all the suggestions.   I went back to the hobby shop and turns out it was a fairly basic mistake on my part and the instructions of the digitrax DHAT wiring harness.  On the Athearn loco their is a long silver conducting piece that fits over the motor connects to the front trucks and the back.  I left this piece on the loco and this was shorting out the leads connected to the trucks.  The store staff removed it, tested and of course it worked.  The instructions never said anything about removing this piece.  My mistake, fairly basic, feeling silly, but learned quite a bit in the process. 

Thanks again.

Chad

  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Friday, October 21, 2011 8:07 AM

 Glad it worked out for you Chad. All so learned something I did not know, that Digitrax now offers a goof proof warranty.

 Cuda Ken

I hate Rust

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