Decoder for N scale Atlas Dash 8-40B

french_guy Jul 4, 2021

  1. french_guy

    french_guy TrainBoard Member

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    Hello all
    I recently purchased an Atlas Dash 8-40B (Conrail) in N scale
    I also ordered a Digitrax decoder DN164A0
    The TCS website says to put some Kapton tape on the frame (I looked at TCS for their detailed instructions...!)
    https://tcsdcc.com/installation/n-scale/1950
    But the Digitrax instruction doesn't mention anything about Kapton tape:
    https://www.digitrax.com/media/apps/products/mobile-decoders/dn163a0/documents/DN163A0.pdf

    So should I apply Kapton tape, or it's not necessary with the Digitrax decoder?

    Thanks
     
    BNSF FAN likes this.
  2. bnsf971

    bnsf971 TrainBoard Member

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    Put the tape anywhere the decoder may touch the metal frame.
     
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  3. MK

    MK TrainBoard Member

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    The more current Digitrax decoders, say, the past two years, have the bottom of the decoder covered in a protective white paper/tape. But I would still put some Kapton tape on the frame below the decoder. It's always good practice. It's thin enough that it won't cause any problems.
     
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  4. Dogwood

    Dogwood TrainBoard Member

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    Use always ever Kapton Tape!!! Kapton tape is also heat resistant. Also in certain places on the frame.
    IMG-20181222-WA0017.jpeg
     
    Last edited: Jul 4, 2021
    BNSF FAN likes this.
  5. french_guy

    french_guy TrainBoard Member

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    OK, so this decoder (DN163A0) is a real pain in the rear with the 2 motor tabs that must go through the PCB into the 2 slots....!!!
    I managed to have it finally installed, but...I now have the "Error to acknowledge from locomotive (308)" when I try to program it with JMRI and DCC++ on the programing track
    Is this error coming from bad/poor contact of the frame with the board, or bad/poor contact from the motor tabs with the board, or it can be both actually?
     
  6. Dogwood

    Dogwood TrainBoard Member

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    Double check the motor contacts under the board and the contacts of the frames.
     
  7. Sumner

    Sumner TrainBoard Member

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    I'd first try to run the loco on address 3 before trying to program it. Does it run as address 3?

    If it runs ok and you are getting the 308 error then from my limited experience it could be any contact between the track and the decoder. This spring I had that error and after just wiping the track down with cleaner I was able to program the decoder. If it is an older loco it could be dirty wheels or dirty contact between the wheels and the frame.

    Are you running DCC++EX by any chance? If so they have help for that problem,

    Sumner
     
  8. french_guy

    french_guy TrainBoard Member

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    I can run the engine with address 03. Forward, reverse, can turn lights on and off...it works just fine
    But once on the programing track, I have the same error message (no acknowledge from engine - 308) - I did clean the wheels and the track, but error remains !!!
    Any idea what I should check next?
     
  9. Sumner

    Sumner TrainBoard Member

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    What DCC command station are you running. That might help someone to give ideas. Also I'd look at the thread ( HERE ) for the problem area that might or might not be addressable but since it is a Digitrax I'd still keep looking at contacts as programming requires the contacts to be doing a better job than running. I don't think you have anything major. Can you change any of the CV's?

    Sumner
     
  10. french_guy

    french_guy TrainBoard Member

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    I'm using DCC++ EX with JMRI (latest Steve Todd's image)
     
  11. Sumner

    Sumner TrainBoard Member

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    I don't have time to look but maybe the link I sent wasn't the right one. Find the one that talks about changing the time period and such for reading the ACK. I'll look later if you don't find it,

    Sumner
     
  12. RBrodzinsky

    RBrodzinsky November 18, 2022 Staff Member TrainBoard Supporter In Memoriam

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    the tabs don’t go through the slots, they push up against the contacts around the slot. One trick I find is to put some solder on the top of the tabs, so that there is a bit of extra thickness for the brass to push up against the board.
     
  13. french_guy

    french_guy TrainBoard Member

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    What is the reason for the slots then?
     
  14. Sumner

    Sumner TrainBoard Member

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    If you still end up having problems I'd do the following. I'll do it the next time I have 308 problems and nothing else is working. I believe you might have to install the latest version of DCC++EX or at least 3.1 if I remember right.

    =======================================================================================

    ===========================================================================

    Sumner
     
  15. french_guy

    french_guy TrainBoard Member

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    Do you know how can I check my current installed version?
     
  16. CSX Robert

    CSX Robert TrainBoard Member

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    You should always try programming (or at least reading a CV) before running. Most systems have reduced power on the program track outputs which can prevent frying the decoder due to a short.

    Try placing a 1k resistor across the programming track while programming(you may have to press down on it to get good contact). If the current draw of the decoder/loco combination is too low for the command station to recognise the acknowledgmnet, sometimes the additional load of a 1k resistor will help.

    Either option will work. According to the Digitrax instructions: "The brass motor contacts should contact the matching pads on the bottom of the decoder and be clear of the metal frame", but "Note: Motor contacts may optionally be bent to engage provided slots on the decoders (See figure 6) Be sure to check clearance to frame after installation"
    I've had good luck with the contacts on the bottom of the board, but I think the slots are for people who feel better with it soldered.
     
  17. Sumner

    Sumner TrainBoard Member

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    Maybe move that over to the DCC++ area here? I know I need to update mine to the most recent version,

    Sumner
     
  18. Dogwood

    Dogwood TrainBoard Member

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    Can you read out the error code in CV08? Does it work?
     
  19. french_guy

    french_guy TrainBoard Member

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    I tinned the pads that make contact with the frame
    I've reinstalled the decoder with the 2 motor tabs going through the slots
    I can still run it with address 3, but can't program it
    I updated my base station with the latest version of DCC++EX (was easy with the exInstaller)
    But same problem: No acknowledge from locomotive (308)...!
    I really don't understand why programing on the track seems SO sensitive, while it runs just fine on the main track with address 03
    So looks like I have 2 options now: put some solder on the tabs and PCB slots , or take it apart 1 more time and re-install it with the tabs pushing from the bottom !!!
    20210705_170123.jpg 20210705_170127.jpg 20210705_173805.jpg
     
    Last edited: Jul 6, 2021
  20. Sumner

    Sumner TrainBoard Member

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    Have you tried from the serial monitor the following command .....

    <D ACK MAX 10700>

    .... you could start with a lower number than 10700. Also in that thread is a short tutorial on how to determine what value might work but I'd just start with about 8000 and work up to the above number or maybe more.

    Fred (flightrisk) has asked people to post the decoder they are having problems with and they will give more detailed help as they have time and will add the results to their database,

    Sumner
     

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