# Digitrax DN143K2 in Kato N Scale RDC



## wongkw (Nov 17, 2011)

Been off the board for a bit due to school and have a short break so doing some work on my trains.

I installed a Digitrax DN143K2 decoder into one of my Rail Diesel Cars (RDC 2 to be specific). Tried it on the track but no forward or backward motion whatsoever. The interior light works when I toggle F1 on and off. F0 also turns on the front and back lights which change colors if I change direction on the controller. I did hear a very low buzzing sound from the loco when I switched it to reverse which went away when I changed direction back to forward...just no motion. The decoder didn't come with any kapton tape nor did the instructions mention having to isolate anything with kapton tape like in other loco's. Didn't get any smoking decoder when I applied power so I'm not sure what the problem is. Any suggestions as to how I should diagnose the problem would be appreciated. 

Kevin


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## NIMT (Jan 6, 2011)

That sounds like the board is shorting out on the frame.
Can you post a picture or two.


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## wongkw (Nov 17, 2011)

Hi Sean,

Here are some pictures as requested, with this installation, I wasn't quite sure what to take pictures so if you need different ones from what I posted, let me know.

Picture 1: top view of front end
Picture 2: view of decoder from bottom of loco
Picture 3: view of decoder from top which shows two tabs to the left that are kapton tape isolated in other locos I worked on (these two tabs are normally held down with a white piece of plastic which I removed for the purposes of the photo

Kevin


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## NIMT (Jan 6, 2011)

Yes I need to see more.
One can you remove the plastic on top of the decoder?
Is there a blue wire that goes rear lights?


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## wongkw (Nov 17, 2011)

Here are some more pictures...

1. Seat assembly removed from loco frame, the 2 pieces face each other when assembled

2. Close-up of decoder that gets sandwiched between seat assembly and loco frame

3. Topside view of decoder pulled away from seat assembly

4. Close-up of motor and loco frame with two motor tabs

The blue wire goes from decoder to the interior light board.

I suspect your guess that the decoder might be shorting out is correct Sean...I just don't know where to put the kapton tape. I'm also surprised Digitrax didn't mention needing to isolate anything electrically unless I did something wrong.


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## wongkw (Nov 17, 2011)

Mystery solved...after taking everything apart for some additional photos in my previous post, I took a close look at everything and noticed the bottom of the decoder had two contact pads right where the motor tabs are. Originally, the motor tabs wrapped over the top of seat assembly and were held in place by a white retaining clip. A close look at the installation pictures on paper and online showed the motor tabs were no longer visible so I tried placing the seat assembly on top of the tabs instead so they would touch the contact pads on bottom of decoder and behold the loco moves now.

I then found the red and orange lights at front and back were reversed depending on detection of travel. A search on Internet showed it was a common problem that Digitrax says can be fixed by changing two CVs. 

Digitrax said this was a challenging installation but I think it wouldn't be as bad if their instructions and photos for this decoder were more detailed and clear.


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## NIMT (Jan 6, 2011)

Excellent!:thumbsup:
Glad to hear you got it up and running.


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