# DIGITRAX SDN144K1E troubleshoot



## AussieNscale84 (Jul 16, 2012)

G'day guys, I am hoping someone can help me out with a drama I have. I have installed a the digitrax sdn144k1e into a kato sd40-2 and it seems that every time it crosses a "rough" section of track i.e. dirty or what ever, the decoder resets causing it to stop and start over and over. So is there a way I can stop the decoder from doing this or am I stuck with this drama for good?
Cheers


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## New Berlin RR (Feb 11, 2012)

yes and no, if your good at electronics you can use (i believe this is the proper name) a capacitor that holds charge so when the engine hits said dirty spot or dead zone there is still power going to the motor/decoder, just make sure you have one that will fit in the space you have and has a large enough capacity for powering the motor and the decoder (and/or sound if applicable) for at least 10 seconds on its own (rule of thumb I use, results and mileage may vary).



other thing that will help is clean the track....seriously if the track and wheels are dirty just clean them, will help you out.

did you clean the wheels of the loco in question, if not clean them, it will help....


others may chime in here with other/more info...hope this at least gives you something to start with.


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## NIMT (Jan 6, 2011)

Keep alive capacitor, should already have one on the board.
I'll look it up and see if there is any fix or add on.


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## timlange3 (Jan 16, 2013)

Considering you should have power pickup on all six axles I think you should check your track!


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## NIMT (Jan 6, 2011)

That model of decoder has an optional capacitor that came with it, if it wasn't installed then yes even a split second power loss will reset the sounds.
Here is a link to the installation of it, http://www.digitrax.com/static/apps/products/sound-decoders/sdn144k1e/documents/SDN144K1E.pdf

If you don't have the capacitor I can send you one, Yes I ship to OZ.


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## yak-54 (Nov 7, 2012)

NIMT said:


> Keep alive capacitor, should already have one on the board.
> I'll look it up and see if there is any fix or add on.


this may help ?

http://www.digitrax.com/static/apps/products/sound-decoders/sdn144k1e/documents/SDN144K1E.pdf


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## AussieNscale84 (Jul 16, 2012)

G'day guys, thanks for your responses. I have cleaned the track thoroughly and it is still doing it, I will go with the capacitor, the only questions with that is, in the bag it came with what looks like 2 different types of capacitors one with hard wires and the other with nothing. So my question is the one with hard wires (looks like the one in the installation guide) is there a correct way of installing i.e. positive and negative etc.
Thanks again


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## JerryH (Nov 18, 2012)

Dirty wheels, dirty track, loose joiners, unpowered frogs, dried out lube on axels and bearings, loose wires, anything that can cause an intermittant flow of power to the decoder are possible contributors to your problem, *particularly in combination*.


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## AussieNscale84 (Jul 16, 2012)

The thing is it only effects this decoder, the other engines/ decoders work fine


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## JerryH (Nov 18, 2012)

Then I would look at everything in the electrical path from the wheel surface to the decoder inputs first. Do not overlook possible intermitant shorts as well as momentary opens.


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## AussieNscale84 (Jul 16, 2012)

Thanks mate


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## New Berlin RR (Feb 11, 2012)

NIMT said:


> Keep alive capacitor, should already have one on the board.
> I'll look it up and see if there is any fix or add on.


Sean I was kinda under the assumption that he had the one with the optional piece, also I was thinking more of it being used to supply power to both the decoder and sound parts along with the motor to keep the engine under power long enough to get through the dead spot(s) he may have.


as for the track if you already cleaned it you may have either loose joiners/rails or not enough power feeds (depending on how large of a layout you have)...another possibility (and more likely) is to look at every thing in the electrical path from the wheels on up IE wheels, wires, decoder, motor, ect, ect...but looking at the track is going to help as well, remember eliminate the obvious and what ever remains however improbable is the solution....


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## AussieNscale84 (Jul 16, 2012)

Thanks heaps guys


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## New Berlin RR (Feb 11, 2012)

no prob aussie, hope our info gets you in the right direction at least


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## NIMT (Jan 6, 2011)

Both the capacitors will work, The smaller capacitor is a SMD capacitor, The bigger one you can use the better it will be.
Yes they are polarity sensitive, just follow the pic.


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## AussieNscale84 (Jul 16, 2012)

yeah but the bigger one doesnt have coloured wires, just 2 hard wire with no plastic cover so I don't know which is pos or neg.


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## waltr (Aug 15, 2011)

On the cap itself is marking of its terminal polarity. There will be a vertical band on one side of the cap with a '-' (or several '-' marks). this is next to the negative terminal of the cap.


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