Class 37 TTS moving on its own

[Phil-Essex]

Hello, I have a Vitrains 37 fitted with a TTS decoder that is at random intervals moving off at a very slow speed of its own accord. I usually only notice when it causes a short by entering the points at the end of my fiddle yard. 

 

Has anyone else experienced anything like this? I use a Z21 and the decoder has a unique address and no other locos exhibit this behavior, not sure what to try!

 

Phil

[mezzoman253]

Hi,

This can be due to having DC(Analogue) running set in CV29.

 

Set bit 2 to ZERO (Analogue mode OFF) in CV29 and see if this still happens.

 

HTH

 

Rob

 

 

[Phil-Essex]

Thanks I’ll give that a try

[cravensdmufan]

On 04/08/2020 at 21:11, Phil-Essex said:

Thanks I’ll give that a try

Did that work for you?  I was going to reply same as mezzoman.  Turning off DC running cured that for me.  I turned  it off on all my TTS chips.

[RAF96]

All recent production Hornby decoders now have DC Running set off as default to preclude DC Runaway.

Check also that your controller is set to Loco Zero off and if on that Loco Zero does not have any throttle applied as stretched zeros that control a DC loco can upset other locos.

Edited November 30, 2020 by RAF96
Added ‘recent production’

[Phil-Essex]

On 23/11/2020 at 20:53, cravensdmufan said:

Did that work for you?  I was going to reply same as mezzoman.  Turning off DC running cured that for me.  I turned  it off on all my TTS chips.

 

When I checked DC running was already disabled so unfortunately the issue remains.

[RAF96]

Does your controller support Loco Zero (analogue). If so select loco zero and ensure throttle is cycled up and back to zero.

The reason is loco zero is controlled by stretched zero bit in the Dcc signal and if any throttle is set it can upset locos equipped with decoders - some decoders are more sensitive than others - TTS is one of the more sensitive souls.