Bachmann dynamis loco shuffle!

[davebem]

Tried searching for this but couldnt find anything.  When I first turn my dynamis controller on, all the locos on the track acknowledge and do a very brief 'shuffle'.  In other words the motor turns for probably half a second, but on the smaller farish locos like the 20s and 25s this is sometimes enough to see them jolting out of their stopped positions and in extremes can shunt wagons off through their buffer stops!  Is this normal behaviour for all dcc controllers?  Is there a way to disable this?  A similar acknowledgement happens when putting locos in double header mode or writing new addresses.

[WIMorrison]

A friend of mine saw this behaviours on some of his locos and when he changed the decoders from the originals to Zimo the dancing of the locos stopped and hasn't happened since. He is using a Z21

[Nigelcliffe]

I'm guessing, but a decoder might be seeing the voltage as "DC" for a while before it then finds the actual DCC signal and decides its on a DCC layout. 

 

So, try disabling DC running in the troublesome decoders.   Or, as Iain says, use better decoders.

 

Or, possibly, go the route of the old ZTC system, where the instructions had words to the effect of  "put an on/off switch between the DCC output and the track.  Leave it off until the system has powered up and appears stable.  Then turn on the track with the on/off switch."  

 

 

- Nigel

 

[Brian]

Get a better DCC system?  Especially as you seem to be N gauge!  

[JimFin]

 

1 hour ago, davebem said:

When I first turn my dynamis controller on, all the locos on the track acknowledge and do a very brief 'shuffle'.

Used Dynamis for years and never encountered that. Suggest you contact Bachmann Europe for technical support - use their enquiry form. I have found a guy called Roger Tozer there very helpful in the past.

[Sir TophamHatt]

While not N gauge, my Prodigy Advance 2 doesn't do this, so would strongly point to the controller / chips doing something weird.

A good way to test would be to make a chip DCC only, then see if that loco does it.