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DCC Decoder install on N Scale Atlas GP-7 and GP-9's

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  • Member since
    December 2010
  • 17 posts
DCC Decoder install on N Scale Atlas GP-7 and GP-9's
Posted by OilJunkie on Monday, January 10, 2011 4:16 PM

I have one Atlas GP-7 and two GP-9's that I want to get decoders installed for.  On Digitrax's website it says to use the DN163A2 on them but the decoder will not fit at all into these loco's without some serious frame modifications (so much for PNP).

Is there any easier way to do this without having to get a different decoder and hardwire it in (which I do not feel like doing)?

And would someone be willing to put them in for me?  I am not that good with the small wiring, and I would have no problem shipping them wherever and paying someone to do it for me. (I live in Alberta, Canada).

Any help would be greatly appreciated!

  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Monday, January 10, 2011 6:22 PM

How old are the locos?  On any of recent, or even just somewhat recent, vintage, that decoder should fit easily.

Jeff But it's a dry heat!

  • Member since
    December 2010
  • 17 posts
Posted by OilJunkie on Monday, January 10, 2011 6:31 PM

I just bought them, but I am guessing they are older locos that have been sitting around for awhile.

  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Monday, January 10, 2011 6:47 PM

If they are not from the last 4 years or so, the boards you have are not going to work.  The decoder David recommended would be the way to go.

Jeff But it's a dry heat!

  • Member since
    December 2010
  • 17 posts
Posted by OilJunkie on Monday, January 10, 2011 6:52 PM

Ah ok.  Well then I will order three of those decoders.  

Thanks for the help!

  • Member since
    March 2007
  • From: On the Banks of the Great Choptank
  • 2,916 posts
Posted by wm3798 on Monday, January 10, 2011 6:54 PM

Atlas has changed the design of the GP 7/9 a couple of times over the years.  It sounds like you have an older version.

The simple identifier is whether the headlights are mounted on a single board across the top of the frame, or in two separate boards, fore and aft.  It sounds like you have the latter.

The TCS CN GP is your best bet.  I've put in a scad of these, let me know if you need any guidance.

Lee

Route of the Alpha Jets  www.wmrywesternlines.net

  • Member since
    December 2010
  • 17 posts
Posted by OilJunkie on Thursday, February 3, 2011 1:36 AM

Lee,

I got one of the decoders and installed it into the GP9.  The light comes on but the loco won't respond to any throttle movements I make.  I did program the decoder and it did accept the CV for the 4 digit address.

And thoughts on what it might be?

Mike

  • Member since
    March 2007
  • From: On the Banks of the Great Choptank
  • 2,916 posts
Posted by wm3798 on Wednesday, February 9, 2011 10:21 PM

Check your connections to the motor (the orange and gray wires) to make sure they are A) secure and B) not making contact with the frame.  Try doing a "read" of the decoder properties on your program track, with the shell off.  If the motor appears to "tick" while the readback is underway, it should work.

It's also possible that during re-assembly, you got something in the gear train out of whack, and the drive is binding.  If the engine makes a little bit of noise, or even if it doesn't, this could be the case.  Beware not to overheat the motor if this is the case.

Try taking the frame apart one more time, inspect the drive train and the motor wire connections, and also, (this is important) make sure the wires all have someplace to be.  I usually cut out the top tab over the DC motor contact to make a little room for the wires to come up through the top.  Having the wires bunched up will cause the frame to mis-align, and therefore cause a bind.

Hope this helps.

Lee

Route of the Alpha Jets  www.wmrywesternlines.net

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