Jump to content

help with speed CVs for an idiot


Recommended Posts

Good afternoon all out there in RM Web world and I trust everyone is well as they can be.

 

I hope that you can assist a DCC novice

 

I purchased a second-hand class 20 (Olivia trains) which is a great model and it all works.

 

I have two issues I wonder whether someone could assist with.

 

Firstly in terms of speed both in forward and reverse in terms of speed settings when moving at 1 & 2 the locomotive crawls at an exceptionally low speed yet as soon as it flicks to 3 it fires up the Turbos and moves far too quickly! Any idea how to correct the overall speed increase?

 

Secondly whilst the red reversing lights stay on all the time in reverse, the white forward lights do not work on speed settings one and three but do on two and four - any thoughts on how to correct this?

any help most gratefully received by this dcc novice

 

I operate from a an NCE powercab

 

thanks

 

tobny

Link to post
Share on other sites
  • RMweb Gold

Welcome to the forum.

 

You've only mentioned speed steps 1 to 3, Have you tried higher steps and, if so, how high did the step count go - 14, 28 or 126?

 

Have you ever altered any CVs (or any loco)? I'm just trying to judge how detailed any attempt to help/guide you needs to be.

Link to post
Share on other sites

Not all decoders are the same.

Over time I have become more fussy with what I use because I have some which don't work as they should. Speed should be more progressive & predictable than you have described. Lights should definitely not depend on speed in the way you have described.

It is possible a previous owner has fiddled with some CVs but most retailers would factory reset the decoder & I would certainly expect this from Olivias.

 

Have you tried reading in CVs before by selecting program track on the handset? The first thing it does is read the manufacturer & decoder type. These should be useful in identifying the decoder hiding away inside.

Link to post
Share on other sites

Headlight going on and off on alternating speed steps is a sign that the command station and decoder do not agree on what the speed packets mean.

 

Either setup the command station to send 14 step speed packets and reset bit 1 in CV29  to tell the decoder to interpret the speed as 14 steps.

Or setup the command station to send 28 step speed packets and set bit 1 in CV29  to tell the decoder to interpret the speed as 28 steps.

  • Agree 1
  • Informative/Useful 2
Link to post
Share on other sites

crossland

firstly thanks! 

 

secondly for a DCC idiot how does one do this

 

either setup the command station to send 14 step speed packets and reset bit 1 in CV29  to tell the decoder to interpret the speed as 14 steps.

Or setup the command station to send 28 step speed packets and set bit 1 in CV29  to tell the decoder to interpret the speed as 28 steps.

 

Link to post
Share on other sites

To chose the value to be written in CV29, try using the calculator at http://www.2mm.org.uk/articles/cv29 calculator.htm

 

Changing the number of speed steps on the decoder will add or subtract two from the current value depending on what the current set up is.  You can read in the current value of CV29 and back calculate to see what that means, or you can just choose the options that you want and calculate the value that should be in CV29.

 

I've no idea how to change an NCE Powercab between 14, 28 or 128 speed steps.  However, if you turn up to full power then you should be able to tell what it's currently set at.

Edited by Dungrange
Link to post
Share on other sites
  • RMweb Gold

Dare we ask what worked?

 

The PowerCab manual will tell you how to use your Programming Track - if you only have the one dcc loco then you can use your layout as a programming track (or remove any other locos from the layout and then use it). Once you get two or more decoder fitted locos you are best advised to create a dedicated programming track to set up/adjust CVs/decoders.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.