# Digitrax Plug in Decoder



## Treeman (Jan 6, 2008)

This may have been covered before, sorry if a repeat.

The Digitrax plug in decoder, DG583AR has a pin missing #7 and #8 is marked not connected. Is this because of a polarity difference between Bachman and Aristo? When installed in a K27 you get no lighting to the loco. I believe the cooling fan and smoke unit are also dead. I'am afraid of the AMP draw to pick up these loads with a decoder output.


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## Bob in Kalamazoo (Apr 2, 2009)

I use a couple of AR583AR's in some Aristo locos and don't have any troubles. I did check things first because of the reports of some Aristo locos being wired wrong (I didn't want to destroy a $50+ dollar decoder right off the bat). Everything worked fine for me. I can't say anything about pins 7 and 8 that are listed as not connected. They don't seem to be necessary on Aristo's locos. 
Bob


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## Treeman (Jan 6, 2008)

This seems to be a problem in Bachman only.


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## StanleyAmes (Jan 3, 2008)

Posted By Treeman on 11 Sep 2012 08:01 PM 
This may have been covered before, sorry if a repeat.

The Digitrax plug in decoder, DG583AR has a pin missing #7 and #8 is marked not connected. Is this because of a polarity difference between Bachman and Aristo? When installed in a K27 you get no lighting to the loco. I believe the cooling fan and smoke unit are also dead. I'am afraid of the AMP draw to pick up these loads with a decoder output. 


The current version of the Digitrax DG583AR is not compatible with the Bachmann Socket.

On the Bachmann locomotives all the locomotive internal current load uses DC current supplied through the + and - pins on the socket. If nothing is connected to these pins the fan, chuff, smoke and lighting will not work properly.

Digitrax currently does not support these pins and hooking them is not an option.

Best is to use a decoder that supports both + and -.

The digitrax decoder can be used if you install a seperate rectifier to provide the needed DC current and manually connect the output of the rectifier to the locomotives + and - connections. You will also have to solder the decoder function outputs to the locomotive board as these connections are on J2 and the Digitrax decoder provides no connections to J2.

Stan Ames


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## Greg Elmassian (Jan 3, 2008)

what pins in the socket are the plus and minus on the bachmann? 

Greg


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## StanleyAmes (Jan 3, 2008)

Posted By Greg Elmassian on 12 Sep 2012 09:09 PM 
what pins in the socket are the plus and minus on the bachmann? 

Greg 

Greg 
Locomotove + is J1-6

Locomotive - is J1-7

Stan


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## Treeman (Jan 6, 2008)

I know I have done one of these in the past. I wired a jumper across two points. These loads were on all of the time. The smoke could be turned off with the switch in the front of the boiler. This would be satisfactory. Don't remember what I did, need to take notes. Just need to bring on the cab and marker lights.


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## Treeman (Jan 6, 2008)

OK, I went back over this. This seems pretty simple to get the marker and cab lights on. I soldered a wire jumper to pin 7 on the decoder marked - Then connected the other end to JI7 on the Bachman board. Looking at the drawing from Bob Grosh, it shows these loads needing ground. This will bring on the fan, smoke, cab lite, fire box, and marker lites. The switches on the boiler front will turn off the smoke and cab lite. Plug and play, not quite. But would work for most of us.


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## Greg Elmassian (Jan 3, 2008)

I've started a page on the "Aristo" socket and the Bachmann variation, and will try to address these issues for people to help them in the future: 


*http://www.elmassian.com/dcc/advanc...dcc-socket*

Greg


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## Treeman (Jan 6, 2008)

Greg, Good to see you found this older thread. How can we get all of the manufactures on the same page? It seems ridiculous that QSI had to make separate versions to work in Aristo, Bachmann, and USA.


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## Greg Elmassian (Jan 3, 2008)

Well, that's a good story, and not one I can really tell here unfortunately (without naming names and saying impolite things... true but impolite) 

Too bad that each manufacturer can't see the overall benefit and realize that they will all profit. 

Greg


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## Cougar Rock Rail (Jan 2, 2008)

Greg, do you know why Aristo says pins 5 & 8 have to be bridged for DCC? What the heck does that mean, that you don't connect the pins to the decoder? I'm about to put a decoder in a friends RS-3. 

Thanks 
Keith


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## Greg Elmassian (Jan 3, 2008)

Yes, originally the idea is that the decoder could "connect" the pins to control power to the smoke unit. 

USUALLY one pin goes to positive and the other to the smoke unit (and from there to ground)... but NOT always... 

I have not tested my Aristo fleet to see what locos are "right" or not, and which of the 2 pins goes to the smoke unit, and if the other is positive or negative. 

The standard just says "connect" them, so it's open season on how they are wired exactly. (Thus one source of frustration by Digitrax). 

greg


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## TonyWalsham (Jan 2, 2008)

Greg, 
Not to be a pedant, but the connection table you are showing at your website has pin # J1-7 as being common ground with blue as the wire colour code. 
In fact the standard DCC wiring colour codes has blue as the colour for output +. So blue should be applied to J1-6. 
I do not know what the DCC colour is for the common ground on J1-7, but I use black.


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## Greg Elmassian (Jan 3, 2008)

Yes, and the polarity of the common is positive... 

The page you are referring to has information DIRECTLY from Aristo... 

http://www.aristocraftforum.com/techinfo/dcc rcc pin connectors/index.htmlhttp://www.aristocraftforum.com/techinfo/dcc rcc pin connectors/index.html

(you have to cut and paste, they embedded blanks in the address)
*  
*The word "ground" is not normally used in DCC... it confuses people since they associate ground with negative... 

In DCC "ground" is really positive... but since you can also find "power and ground" I find it best to not use the term ground also. 

I'm going to expand the Aristo socket page, but you can see inaccuracies from Aristo right off huh? 

Greg *
 *


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## TonyWalsham (Jan 2, 2008)

Understood now I see the AristoCraft table. They got it wrong as they often do. 
For the sake of clarity to other users how about running a second table that points out the AristoCraft error and shows the correct labeling with the + v output marked as blue and not the ground labeled as blue? 

I admire your ability to decipher the gobbledygook that passes as AristoCraft wiring. 

BTW it was Paul Housey who told me the story about who designed the original interface. He had been approached by AristoCraft to submit his ideas for a socket and asked me for mine. I don't know if our ideas were ever submitted to AristoCraft or not, but eventually Paul advised me that Digitrax got the nod and then why the Digitrax decoder design and the production socket were not compatible.


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## Greg Elmassian (Jan 3, 2008)

Yes, the page is developing right now... I want to be sure I have all the Aristo stuff in there as documented. 

Then I want to get the Bachmann story, will get most from Mr. Ames if possible. 

Then, corrections to the published data, like what you have found, and finally tips and techniques for using various "pnp" decoders, including yours (although I believe yours is very compatible). 

Greg


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## TonyWalsham (Jan 2, 2008)

Great idea Greg. Should be a very valuable resource. 
Stan is definitely the best resource for Bachmann information. 

Whilst you are at it, could you check out the "old wives tale" about the SD-45 whereby some of them only isolated the track on one side? That meant if the loco was run back to back with another identical SD-45 they could short out the BATTERY option that supplied the loco via the pigtails. Also the "old wives tale" about some of the Dash 9's having reversed pigtail wiring compared to other AC locos. Never mind the mis-wired Pacific and Mikado tenders. In my opinion those problems are all related the AC socket performance. 

Yes my PnP ESC will work correctly with either brand socket, except for one thing. 
It was designed specifically for the AC socket version but took into account the slight variations of the Bachmann version. For example the motor output polarity is backwards for Bachmann compared to the AC so I have a programmable default direction at start up to correct it.


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## SteveC (Jan 2, 2008)

Posted By Greg Elmassian on 01 Jun 2013 06:39 PM 
Yes, and the polarity of the common is positive... 

The page you are referring to has information DIRECTLY from Aristo... 

http://www....index.html

(you have to cut and paste, they embedded blanks in the address)
*
*The word "ground" is not normally used in DCC... it confuses people since they associate ground with negative... 

In DCC "ground" is really positive... but since you can also find "power and ground" I find it best to not use the term ground also. 

I'm going to expand the Aristo socket page, but you can see inaccuracies from Aristo right off huh? 

Greg *
* Nothing wrong with the space characters, per se, you've just got the closing anchor tag in the wrong place. However it still causes the resulting hyperlink to fail because of the mismatch in the two (i.e. actual URL with the URL encoded space characters & URL displayed text with the plain space characters), which causes the URL to be truncated when parced.


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## Greg Elmassian (Jan 3, 2008)

Actually what happened is trying to copy and paste put the %20 in where the space was... then those characters are interpreted literally... at least that is what my cursory checking told me. 

On top of that, I did indeed get truncated and that's when I gave up because it was wasting too much time to figure out... 

Back to the topic: 

I'll check the SD-45's Tony, but the problems have found are limited to motor wired backwards, and headlights wired to the motor and not the socket. Very frustrating. There is a version of the original QSI where there is a limitation in consisting if the motor is wired backwards. When I reversed the motor connections then the lights were backwards! 

There definitely was a batch of Dash 9's with some reversed wiring and many of the ones shipped this year have some major problem in the socket where you cannot use any decoder. (many people have gotten new mother boards). 

Yes, the older steamers have wiring problems in the tender that can be corrected, but the battery switch only disconnects the battery from one side of the wiring and the loco wheels are always connected. 

I hope to make it useful, I might not be able to document everything, but I will put in the things to watch for, and how to find them and how to correct them. 

Regards, Greg


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