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Sproblem with tts decoder

railshed

15 posts

On fitting a R8103 TTS decoder into a class 47, which I purchased secondhand which had the decoder removed, it takes off in one direction even with the power off on the control, also if I change direction on the controler it shows a short? the loco runs perfect on dc. is this a decoder fault? or a problem with the loco? the decoder was only recently purchased I have seen on the Hornby dcc page that there as been problems with some decoders, have I got one?????

 

Rog (RJ)

2216 posts

have I got one????

 

Could well be.

Rog :-) I don't model anything in particular, I just play trains. Living on the South side of Nottingham. Keep taking the tablets. https://www.modelrailwayforum.co.uk/

WilliamDavid

747 posts

This does not seem to match my issue with the Class 47 decoder.

I have just been talking to Hornby Support, and they don't know of any issues.

They are looking into mine.

WilliamDavid

747 posts

Try setting CV10 to turn off dc running and see what happens.

Ericm0hff

5862 posts

What controller are you using, Shed?

There have been some reports that TTS decoders don't like some controllers! See Admin's post - Hornby TTS Decoders

if it works first time, you did something wrong!

Fishmanoz

9836 posts

Taking off flat out is called DC Runaway and happens when the decoder fails to recognise that a signal is DCC, and thinks therefore it is analogue.  It then runs off at full speed because DCC always has full volts to the track.

 

You can turn off DC Running but WD has his CVs crossed.  It is controlled by bit 2 of CV29 meaning you have to read the value of the CV then write a value 4 less.  So if you find the default value of 6 there, change it to 2.  But if you have the basic Select controller, it can’t do this unfortunately.

 

It could be that the decoder is faulty but it may also be that your track and wheels are not spotless and/or your pickups aren’t tensioned on the wheels properly.  Check out all of this and see if anything changes. Let us know, along with what controller you have.

and thanks for all the fish

railshed

15 posts

Thanks for the replies, I use a select controller to set the addres on the test track, I run my layout with Railmaster Pro Here is the next enquiry, how do you get up the page for CV's ? being 71yr old I know how to use a computor but this has got me? can anyone take me through it, ie get the page up and make adjustments as required without messing up the system.

Chrissaf

12056 posts


Community Moderator

Put the loco on the 'programming' track piece connected to the 'Prog A&B' output on your eLink (or Elite).

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In RailMaster (RM) open the 'Loco Setting' screen by pressing the 'Loco Setting' icon (highlighted in Yellow in image).

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The 'Loco Setting' screen will open. Assuming that you have already added your loco to your RM loco roster, your loco should be listed in the Yellow highlighted box. Click your loco entry so that it populates the boxes in the Red highlighted area, then click the " i " icon highlighted in Green.

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If you haven't yet added your loco to the RM Loco roster i.e it is not listed in the list highlighted in Yellow, then follow this link below for instructions on how to do that first.

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https://www.hornby.com/uk-en/forum/loco-registration/?p=1

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NOTE: If all you want to do is change the 'Loco Decoder DCC Address' and nothing else, then instead of clicking the " i " icon click the Loco icon to the left of the " i ".

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When you click the " i " icon. The read / write CV screen will open. Set the range of CVs you want to Read in the boxes highlighted in Green, then click the 'Green Tick' in the bottom right. Note that this green tick is the READ CV button and NOT the 'Save Changes' button. In most cases you only really need to set a fairly short read range to read the basic CVs. Say for example from 1 to 40 this will save considerable time compared to reading the full range.

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Amend any CV values in the list that you want to change by clicking the value box, deleting the current entry and then typing the new entry you want. Once you have made the changes you want. Click the 'PEN' icon highlighted in Yellow. This will initiate the writing of the CVs to the loco that is sitting on the programming track. After each CV value is written, the value will be read back to show as the new value in the box in a different colour. If it doesn't read back the value you want then something has gone wrong and you should try again. Once happy that everything is as you want it, then exit the screen using the RED cross in the bottom right.

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You can now re-mount your loco on the main track and test that the CV changes you have made do what you want on the track.

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Note: If when clicking the Green tick to read the range of CVs selected in the range boxes, the CV value fields return a high number of 255 values, then this means that RM cannot see the loco decoder on the program track. This will probably be due to a poor electrical connection between the 'Prog A&B' output on the controller and the Loco decoder. This might be due to poor wire termination on the controller terminals or programming track piece, dirt (oil and grime or dust) on the programming track. Dirt on the loco wheels. Or poor contact on loco pickups. Make sure everything is super clean and shiny and try again.

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Chris........ Making the wood in the trees visible.

railshed

15 posts

Thank you, that explains it all in terms that I can understand, unlike the pdf files which lost me totally after the first page!!!! I will keep you informed of the outcome.

railshed

15 posts

OK did everthing that CD listed but still no joy? but the one thing that surprised me is that in the cv list it is showing that the chip version is R8249 4 function, on the box it came in the lable reads R8103 is this correct? and yes everything is clean, 

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