Help programming a Soundtraxx Soundvalue Decoder in a Bachmann RS3

[JWhite]

Got a good deal on one of these and I’m having problems getting the speed table right.

I’ve got the momentum and sound the way I want it, but I can’t get it to run slow.

im using the latest version of JMRI. I don’t know if the speed table isn’t loading or if I’m doing something wrong.

The only other decoder of that type I have is in a Spectrum 4-8-2 that came with factory sound. It’s the soundtraxx model Bachmann used before they came out with the Soundvalue line so it might not be the same.

Jeff White

Alma, IL

 

[rrinker]

 If it started too fast before tryuing to set a speed table - you can;t make it start any slow with a speed table. No speed table configured, CV2 set to 0 (or 1, some decoders can;t set it to 0) is as slow as it will start up on step 1. No amount of speed table adjustment can make that slower.

 One thing that helps most any bachmann loco is to remove the capacitors that are across the motor wires. On some locos these are on the motor itself, on others they are on the circuit board. These interfere with the DCC drive signal and it's amost universal that they run better simply by removing them, no other adjustments.

                                    --Randy

 

[MisterBeasley]

I have a couple of Soundvalue decoders.  They both did jackrabbit starts and would not run slowly out of the box 

I adjusted VHigh, the max speed, much lower.  Yes, that limits the top speed, but it scales all the other speeds and slows the engines down, even on startup.

[RR Baron]

 

In addition to info provided - to obtain very slow speed requires motor control adjustments to   

CV 10, Back-EMF Cutout

CV 209, Kp Coefficient

CV 210, Ki Coefficient

CV 212, Back-EMF Feedback Intensity

 

One way to do this is covered in Strategy for CV Optimization section Tsunami Diesel Sound User’s Guide, page 49. (For context read pages 48 – 50)

https://www.soundtraxx.com/manuals/usersguide_diesel.pdf

 

Realize the Sound Value decoder factory installed by Bachmann in their ALCO RS-3 is not a Tsunami decoder; however, the Strategy for CV Optimization part of the Tsunami documentation is applicable.

 

 

NOTE -  while a Sound Value decoder supports 3-point speed curve it is disabled in the RS-3. The default is the User-Loadable Speed Curve 28-point speed curve.

See https://www.soundtraxx.com/factory/images/bachmann/pdf/ho_alco_rs3_sv.pdf

 

Caveat: Do not be surprised if you come across misprints when comparing the  document in the link to the installed decoder.  

 

RR Baron

 

 

[rrinker]

 Something else to try, try runnign the loco on 128 speed steps instead of 28. Depending on your system - what DCC system are you using? In every MR review ehere they bother reporting it, the startign speed on step 1 is ALWAYS lower usign 128 than it is with 28. For the same reason that setting CV5, each step is a smaller increment.

 This does not preclude using a 28 step speed stable to custom map the performance, but I have never bothered using speed tables, as any tweaking I've had to do can easily be accomplished using a 3 step curve with CV2-6-5. Some decoders do not support CV6, since it is listed as 'optional' in the NMRA standards, but I simply do not use any decoder that does not support CV6.

                                 --Randy

 

[JWhite]

Thanks for all the help.  Between this thread and a video I found on YouTube I've got it running pretty much the way I want it to.

Jeff White

Alma, IL