Loco lurches after stopping with ESU LokSound XL 4.0

Ralphmp

Ralphmp

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Like several others I've converted a Bachmann Thomas the Tank to DCC using an ESU decoder (LokSound XL 4.0). Everything seems to work as it should with one exception - when I bring the loco to a halt it stops and then immediately lurches in the direction it was previously travelling in.

I have a Massoth 1200Z set-up with up-to-date firmware on base station and Navigator, and none of my other locos do this. However, they are all LGB, and either have factory-fitted decoders or Massoth ones I've fitted. TTT is only the 2nd Bachmann loco I've owned and this is my first ESU install, so it's entirely possible I've made an error either in the installation or the decoder programming.

I've been through the ESU decoder manual as best I can and can't see anything that describes either the issue I have or how to deal with it. However, I confess I've struggled to follow the manual as I find the layout and the fact it covers multiple versions of the LokSound decoder confusing.

I tried a number of searches on the forum but couldn't see anything that seemed relevant. Do the symptoms I've described sound familiar to anyone, and if so, any hints on how to deal with them?

Thanks.
 
The CVs 55, 56, 57 adjust the starting and stopping with BEMF.

If adjusting the CVs does not stop the 'lurch' then it sounds like something to do with the onboard 'power buffer'.
The buffer can cause the loco to carry on moving for a short while if there is DC power in any way.
This feature can be disabled by using CV29 to disable DC (analogue) functioning.

If you have tried all the above and are still getting the 'lurch', there could be some DC 'leaking' from the central station or the buffer is maybe 'seeing' some DC.
Also if there is any capacitor across the motor (Bachmann tend to use polyfuses) then this can upset the BEMF.
 
Thanks for the suggestions. I'll give them a try tomorrow.

The point on capacitors is interesting as there are some "electronics" attached to the motor which I left in place when I fitted the decoder. As previous posters who have done a TTT decoder install suggested, I used the motor feeds from these "electronics" rather than connecting directly to the motor; if the CV adjustments don't do the job then I'll try going direct.

Best wishes
 
Remove the capacitors that are across the motor.

If you switch of the load compensation does the problem persist (Set CV56 to 0 to switch it off, 255 to switch it back on again)?

You can also try getting the decoder to perform an automatic calibration for that motor which sets CVs 51 thru 55. Section 11.1.3 in the manual describes how to do this.
 
I've also had this issue on my V4 installations. I did find that running the auto tune improved things but didn't fully solve it. Not got round to further tweaking as yet.
 
To everyone who provided helpful suggestions

Just wanted to apologise for not saying "thanks" earlier - I have ongoing health issues which kind of take over from time to time (and take precedence over trains) and I've been through one of those periods over the past month or so.

Hopefully the weather will stay kind this weekend and I can try out your suggestions and post the results.

Thanks again.
 
From memory, I think the auto tune is cv54. To place the loco on the track(ideally straight) set the direction, then set cv54 to value 0. Make sure F1 is off before programming the cv. After programming, turn on F1 one, which should launch the loco at full speed for about 3 secs. Then it should respond correctly.

I've also found it useful to then read back the values to the project file and save them to the project. Means you don't need to repeat auto tune if want to change the sound file/s.

Hope this helps.
 
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