Slow speed with NCE decoder

[Neil Robinson]

I'd appreciate any advice on the issue of an abrupt stop on a Bachmann Connie with a NCE 408 decoder. The original Bachman circuity has been retained with the decoder wired as Bachmann's diagram making allowances for the different decoder's wiring.
I've tried programming a speed curve with an almost flat lower end. That is to say speed steps one to six start at one and increase one unit at a time. I also tried setting speed step one to zero, step two with value one and so on for the next few steps. I must have done something right as the acceleration and deceleration is more gentle than before and also than when the curve is switched off with CV29 bit 4. However the loco's speed change from the lowest speed step to stop is too great.
Tweaking CVs CVs116 and 117 doesn't seem to make any difference. Neither do CVs, 23 and 24 but I don't know if these are valid for this decoder. The decoder was purchased new in November of last year so should be the latest version.

 

[Greg Elmassian]

so:
first momentum off CV's 3&4, set to 0
did you play with CV's 2 and 5? try setting them to their default, sometimes decoders have an interaction between these and a custom speed table.
set CV6 to midpoint, same reasoning as above. (set to 0 actually sets it to 128)

I hope you have the manual, then you would not have to think about CV116 and CV117, since they are not in this decoder!
You should leave CV's 23 and 24 at zero (they are in the manual and the decoder)

Also, turn CV65 off, you may have it set too high (kick start)

At this point try your custom speed table.

Some other questions, you are running this in 128 speed step mode, right?

Bottom line, turn off acceleration until you get the speeds right. then you can turn on acceleration and tune that to your liking.

You have mixed up the meanings a bit between speed and acceleration in your post, but I'm pretty sure you know the difference... divide and conquer, speed first acceleration second.

Greg

p.s. if you don't have the manual, email me... greg@elmassian.com

 

[Neil Robinson]

After a fair bit of experimenting the NCE decoder was replaced with an ESU Lokpilot XL V4
This decoder has additional motor control CVs (51 and 52) specific to the lowest speed steps.
For some reason this was needed with this loco. However the I've found the NCE decoder to be O.K. with other locos.