Bachmann DCC GP7's and JMRI DecoderPro3

[Bendtracker1]

A friend has wanted to get into the wonderful world of speed matching.
He's contacted me,  and wound up sending me two of his Bachmann GP7's that are DCC equipped so I can see what if any CV's are modifyable.

I got them in the mail today and after work I ran down stairs to the laboratory. Placed them on the programming track and did a "READ" on them with DecoderPro3.

One was advanced consisted, the other ran fine.

So I setup JMRI with a "New Loco" to read the chip, filled out the roster page and saved the file. Next I tried to change CV19 to "0" to clear out consisting and ............NOTHING! 

So I tried setting the program type to all of the other types one at a time with no luck.
Even the one that runs I cannot seem to change any of the CV's Period?
I should mention this, I am trying to program them with my Digitrax Super Chief and he uses an NCE system.

Has anyone ever used JMRI to program Bachmann's factory decoders?

[sizemore]

Sounds like you need a ballast across the rails when programming. Try a 12V bulb between the rails to provide the necessary ballast.

The S.

[Bendtracker1]

Sounds like you need a ballast across the rails when programming. Try a 12V bulb between the rails to provide the necessary ballast.

The S.

This I haven't tried yet, but I will.  I did try to program a couple of my Atlas units with TCS and Digi decoders and they worked just fine.  I'll try the bulb or resistor trick.
Thanks S!

[jwb]

When you say "Bachmann DCC GP7", are you referring to the sound-equipped version or the simple DCC version? My understanding is that the non-sound has a Lenz decoder, while the sound ha a reduced-feature Soundtraxx board. The interesting question is documenting exactly what's available on the Soundtraxx, which isn't well covered in the product guide.

[Bendtracker1]

When you say "Bachmann DCC GP7", are you referring to the sound-equipped version or the simple DCC version?

This is just a simple version. Wasn't aware the GP's had a sound chip option?

My understanding is that the non-sound has a Lenz decoder, while the sound ha a reduced-feature Soundtraxx board. The interesting question is documenting exactly what's available on the Soundtraxx, which isn't well covered in the product guide.

Well when JMRI read the CV's on these two chips, they came up as mfg ID 101, which is a Soundtraxx board.  The two chips I'm working with are non-sound boards and I think they are from an early batch of these GP's.
I'm not too familiar with Bachmann decoders.  From what I've found, there really isn't many CV's that can be adjusted regardless.

When I look at the pages that JMRI pulls up, they show them as having the ability to change quite a few CV's.  But nothing I change makes a difference.  One thing they show is that I can change from the Basic [and I mean basic] Speed table to the full speed table.  But nothing changes after I "Write Full Sheet".  It also shows that CV19 is "0" and not to what the advanced consist number is on both pages.  I can change them on both pages, but nothing sticks, so when I call them up on the throttle I get the chip number and it shows it's Consisted.

[jwb]

I have a couple of Bachmann sound locos, and my experience in fact is that the speed curves don't seem to be able to be changed. But this applies to sound locos. Other Bachmann non-sound locos either have just a socket, so you can add your own decoder, or a low-end Lenz decoder that can easily be replaced. It sounds like you're dealing with the Soundtraxx board here.

[Bendtracker1]

This is what it appears to be, a low end non sound chip that only a few things can be changed.
i think if this is truly the case, I'm gonna try to talk him into ripping the low end boards out and installing a hardwired chip like a DZ125 or TCS version.
I'm glad I never invested in any of these units. 

[sizemore]

Is this HO or N?

The S.

[Bendtracker1]

Sorry S!   

It's an N scale version.

[peteski]

The basic Bachmann DCC decoders are VERY basic.   See http://www.bachmanntrains.com/home-usa/images/44913_Decoder_IS.pdf

They don't even support the 3-step speed tables!  BTW, ID=101 is not Soundtraxx - it is Bachmann.  They make their own low-end decoders. See http://www.nmra.org/sites/default/files/appendix_a2c_s-9.2.2.pdf

[sizemore]

Just put a 12V bulb across the programming track. That should allow you to program it with your DCC system at a minimum. Should be the same with JMRI, but I've never tried.

The S.

[seusscaboose]

Use the bulb trick
It works

Better solution = rip out the decoder and hardware new

Ep

[woodone]

If you are reading back the manufactures ID of 101, that is a Bachmann decoder not a SoundTraxx,
unless I missed something.

[Bendtracker1]

OK, A couple of things:
1- I stand corrected on the MFG ID number, 101 is Bachmann
2- I tried both the bulb and the resistor trick on the programming track using JMRI with my Super Chief, no luck.

I believe that JMRI has the pages for the full speed table but the cheap a$$ decoders do not make use of them?

Last night after messing around some options, I did a little tinkering and then some grinding and filing and was able to get both an Atlas DC and DCC ready GP7/9 chassis to fit under the Bachmann shell.  I need to do a little more grinding and filing as the shell has a slight bulge along the sills.  But it fits well enough that the body mount couplers line up perfectly.

The other option was as Eric stated; Rip out the old POS decoder and hardwire a new one in place.  I think the new chassis will work the best in this case.

The reason for keeping the Bachmann shells is that they are custom painted and he wants to keep them for sentimental reasons.

Thanks for the input.

[sizemore]

IIRC the Bachmann decoders are very primitive 28 step Lenz decoders, which is what makes these locomotives affordable. One a few of them can be changed they're not really meant for full-tilt programming. Also it helps to give any of the new Bachmann loco's a good cleaning as they are overlubed direct from the mint.

Programming issues, and poor running are often signs that the lube is creating problems at the pickups. It helps to clean them with a plastic compatible contact cleaner and polish the frame portions that make contacts with the...contacts.

The S.