# Changing A Decoder Address



## nemo (Aug 20, 2011)

Good afternoon:

I'm having an issue changing a Bachman SpectrumSD-45 Loco which is DCC. The locomotive is equipped with a 28-speed step decoder that is factory-programmed to address button 3 on NMRA-compliant DCC system. Trying to change address 4 to 7604. Following Digitrax Zephry manual Section 16.2 Changing & Reading the Decoder Address (Page 24 thru 25). Address stays at 03

Thank you,
Bill Neimeister


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## tankist (Jun 11, 2009)

nemo said:


> Following Digitrax Zephry manual Section 16.2 Changing & Reading the Decoder Address (Page 24 thru 25). Address stays at 03


different decoders may have different CV in need of change when re-addresing. programming a short address may be different then long address. digitrax system probably describes working with digitrax decoders. you need to consult the decoder documentation instead.

with that, i'm aware that no documentation is included with your engine. which is a big failure on bachmans part as their decoder is not standard. i had one of those bachmann dcc installed engines myself. when trying to program mine i definetly did not touch the right ones, as engine behaviour became erratic - i think that i touched CVs responsible for acceleration and speed curves instead. i did not succeed in finding the documentation at that time. 

other bach owners might help you better, as i know that this is not the solution you want - but i just replaced the decoder and forgot about the troubles. budget decoders like DH123 are worlds better: 128 speed step (why on earth would you use anything else), quiet drive, comfortable speed curve adjustment. today i just factor in the cost of replacement decoder if i buy a spectrum engine. 
or did they suddenly started to use better decoders today?


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## Artieiii (Apr 25, 2011)

My Bachmann K4 4-6-2 that I repainted to resemble the blue comet came with a Bachmann DCC chip onboard. When I ran it for a test run it would respond to DCC commands for about half way around my track then quit responding to any input. No idea what the problem was but I replaced it with a Digitrax SDH164D to add sound and she runs like a champ now. Some people suggest removing the capacitors on the main board but I just cut the wires on the Bachmann chip and soldered on the SDH164D's leads to the 8 pin plug and all is good now.
-Art


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## nemo (Aug 20, 2011)

Gentlemen:
I emailed Digratax and this is what they suggested:

Zephyr will not program a Bachmann decoder unless you place a "load" on the Program circuit (across the program track or between Prog A and Prog B) by using a 12 volt bulb or a resistor such as a 120 ohm resistor (you have one in the LT1 packet that came with the Zephyr). With the "load" it will program the Bachmann decoder.

Do you know what they mean by a load across the the program circuit?

Digitrax
Tech Support
[email protected]
2443 Transmitter Rd
Panama City, FL 32404
850-872-9890


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## Artieiii (Apr 25, 2011)

nemo said:


> Gentlemen:
> I emailed Digratax and this is what they suggested:
> 
> Zephyr will not program a Bachmann decoder unless you place a "load" on the Program circuit (across the program track or between Prog A and Prog B) by using a 12 volt bulb or a resistor such as a 120 ohm resistor (you have one in the LT1 packet that came with the Zephyr). With the "load" it will program the Bachmann decoder.
> ...


Load means "resistance" to the flow of current. As the instructions say put a resistor there to put a "load" on the flow of electrons or a light bulb will do the same thing. I can't explain why the extra "load" or "resistance" is needed but if that's what is needed, it sounds like an easy fix. My power cab does not have this requirement.
-Art


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## xrunner (Jul 29, 2011)

Here's a list of the Bachmann CVs. I was looking into it myself the other day becasue I have a Bachmann engine -

http://www.bachmanntrains.com/home-usa/ez_content/1_Amp_Decoder_Instr.pdf

According to some people, it's really a Lenz decoder.


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## gc53dfgc (Apr 13, 2010)

I had a bachmann DCC equipped SD40-2 Messed with it a littel never tried to program a CV and it fried in a little over a week. So I went all in and bought a Soundtraxx Tsunami sound decoder and installed that with a speaker and some super detail parts radiator fans and grilles to top it all off I also added ditch lights and it now looks like a brand new better then before engine (same with the programming)


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## nemo (Aug 20, 2011)

Gentlemen:

I even tried to read CV values in my Broadway-Limited 51219 Bluline USRA Heavy Mikado 2-8-2, Erie# 3204. And I still get programming error message (d nr) means the DCS51 was not able to read the decoder. I believe I have a faulty ZEPHRY xtra. Currently working with a Digitrax Technician on my issues


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## nemo (Aug 20, 2011)

No there is not any "issue" in the programming circuit of the DCS51 and you in all probability will not be able to read any BLI decoder, particularly Blue Line ones.


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## Massey (Apr 16, 2011)

are you trying to read the decoder on the main or on the programing track? If memory serves me, you can only read the decoder from the program track.

Massey


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## nemo (Aug 20, 2011)

I'm trying to read the decoder address from the program track.


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## waltr (Aug 15, 2011)

On a DDC Program track the 'read-back' is done by turning on the motor for very short periods. This 'loads' (causes current to be drawn, NMRA spec is >60mA for read-back) the Command station's programmer output circuit and this can then be detected. 
All Decoders that meet the full NMRA specs will do this. However it seems that the Bachman decoders do not. Therefore the suggestion of adding a fixed load to the programming track. This is done by connecting a resistor across the rails of the programming track.
So assume a track voltage of 12V then for a min load of 60mA a 200 Ohm, 1W resistor is required (E/I = R). To ensure a load greater than 60mA use a smaller value resistor. I have used a 120 Ohm, 1/2W resistor to program decoders that I didn't have a motor connect to it. 

Another point:

CV1 is a 2 digit address. For a 4 digit address two other CV's are used then the 4 digit address is enabled in another CV (CV29 on a DigiTrax and SoundTraxx decoders). 
Does the Bachman decoder even support a 4 digit address?


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## xrunner (Jul 29, 2011)

waltr said:


> All Decoders that meet the full NMRA specs will do this. However it seems that the Bachman decoders do not.


I just bought a new Bachmann GP7 several weeks ago and the paperwork specifically states the decoder is NMRA compliant in several places. :dunno:



> The factory installed advanced DCC decoder has an NMRA conformance warrant and is compatible with all NMRA-compliant DCC systems.
> 
> Features of the decoders with these locomotives include, 2 and 4 digit addresses, 28 and 128 speed steps, advanced consisting, dimmable lighting, settable acceleration, deceleration, starting speed, and much more.


http://www.bachmanntrains.com/home-usa/ezcommand_2010.php?ezpage=2


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## waltr (Aug 15, 2011)

> specifically states the decoder is NMRA compliant in several places.


That's the problem since the NMRA "Service mode" spec (RP-9.2.3) is a "RECOMMENDED PRACTICE" not a "STANDARD". 
A decoder does not need to meet the RP specs to be "compliant"!!!!!
A decoder only needs to meet the "STANDARD" specs (S-9.1 & S-9.2) to be compliant.

http://www.nmra.org/standards/DCC/standards_rps/DCCStds.html

Well at least there is a 4 digit addressing. Anyone know which CVs to write to to get 4 digit address working for the OP?


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## xrunner (Jul 29, 2011)

waltr said:


> That's the problem since the NMRA "Service mode" spec (RP-9.2.3) is a "RECOMMENDED PRACTICE" not a "STANDARD".
> A decoder does not need to meet the RP specs to be "compliant"!!!!!
> A decoder only needs to meet the "STANDARD" specs (S-9.1 & S-9.2) to be compliant.


Well I'm getting my DCC controller Monday so I'm going to be in full learning and experimenting mode after that but my first questions is:

If a practice is recommended by the NMRA, what keeps it from being _required_ for compliance. I.e., if some of these functions are so useful why are they not required for compliance?


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## bradimous1 (Mar 3, 2010)

xrunner said:


> If a practice is recommended by the NMRA, what keeps it from being _required_ for compliance. I.e., if some of these functions are so useful why are they not required for compliance?


just a guess here... but I think with the current setup, this allows for different levels/costs of decoders to allow more people to use "complient" decoders. again, this is purely speculation and opinion.


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## waltr (Aug 15, 2011)

Compliance is just so a decode's basic functions will work on systems from different manufacturers.

See:
http://www.nmra.org/standards/candi/dccconformance.html

For the NMRA's definitions for testing DDC to conformance.
This requires meeting the specs of S-9.1 & S-9.2 only.

Now other decoders do meet the specs of the RP's as well. Here is what is in the Soundtraxx document for a TSU decoder:


> COMPATIBLE WITH
> THE NMRA DCC STANDARDS
> AND RECOMMENDED
> PRACTICES


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## xrunner (Jul 29, 2011)

waltr said:


> Compliance is just so a decode's basic functions will work on systems from different manufacturers.


Waltr,

I understand the point you are making but my point is more fundamental than that. I'm asking why the minimum compliance standards are the way they are and include nothing more than that.

It's kinda like asking why does baseball have 3 strikes and your out instead of 4 or 5. You would say, well that's the rules, and I would ask you well why is it the rules? Is there a reason for it or is it simply an arbitrary set of minimum standards? If some very useful operations are not included in the minimum standards, then why not?


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## waltr (Aug 15, 2011)

Sorry xrunner,
I thought that when you read the all info on the NMRA website I linked to you would understand.


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## xrunner (Jul 29, 2011)

waltr said:


> Sorry xrunner,
> I thought that when you read the all info on the NMRA website I linked to you would understand.


Understand what, specifically?


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## cabledawg (Nov 30, 2010)

Here's what Bachmann says about thier current decoders.

http://www.bachmanntrains.com/home-usa/products.php?act=viewProd&productId=1464

I have one of these and have never had any issues with programming, but then again I've been using PR3/DecoderPro since I bought the Zephyr. The Bachmann decoder seems to have all the "bells and whistles" as a Digitrax DH123.

As for the stanards question: the standards are the way they are because the NMRA made the rules. Maybe they voted, maybe they drew ideas from a hat, who knows. But a governing entity in the world of model trains said these things should be standard and so they are now. Being compliant simply means that it works with other NMRA compliant DCC stuff. Like standard AC power in the US being 120VAC. Why anyone chose that number doesnt matter. What matters is that anything built to run from a standard wall socket will use 120VAC for compatibility.


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## xrunner (Jul 29, 2011)

I just got my Digitrax system and it runs the Bachmann GP7 great! Fantastic! Wonderful!. I love DCC ...

But I cannot change any CVs in the d*mn thing, even the address of the engine. I've played with it for 2 hours and I can't change any CVs nor can I read back any CV location data. I have a programming track set up and have tried the resistor trick with 100 & 1k and it doesn't take the programming. I also tried all four programming modes, even though I don't know exactly what the differences are - no luck. When I read back CVs all I get is NoData. It acts like it programs it but when I place it back on the main line it is still set to address 03. Runs like a top but I can't change the address. 

Any other ideas?


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## NIMT (Jan 6, 2011)

I wish I had one of these to test it out for you. I have had programming issues with older lenz decoders but have not run into a newer one in a while now.


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## xrunner (Jul 29, 2011)

NIMT said:


> I wish I had one of these to test it out for you. I have had programming issues with older lenz decoders but have not run into a newer one in a while now.


I have a Digitrax decoder coming in Wed. for my Kato and that will help me know if I'm doing something stupid or if it's the Bachmann that is at fault. I am searching the Internets for a solution, but so far most of the things I've seen I've already tried. I will search this forum more also.

I am quite pleased with how the little engine runs, lights can be switched on and off, reversing is cool. It's all good except for programming the address.


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## xrunner (Jul 29, 2011)

I found the problem - my bad. I had connected one of the programming track wires to ground. Now it works just fine and no resistor is required. Yay!


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## NIMT (Jan 6, 2011)

Excellent for you!!!:thumbsup:


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## xrunner (Jul 29, 2011)

FYI - I read CV 8 and it =101: Bachmann Trains


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## NIMT (Jan 6, 2011)

Yea they have the decoders programed to say that, it beats it saying Chinese piece of...work!


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## Massey (Apr 16, 2011)

Xrunner, do you have a similar convo going in another thread or did I lose my mind and my post?

Massey


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## xrunner (Jul 29, 2011)

Massey said:


> Xrunner, do you have a similar convo going in another thread or did I lose my mind and my post?


It's similar but not exactly the same.


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