J36 confusing TTS decoder

[JWRStation]

I have a new J36 with TTS sound.  It has been on display for over a year as i have lots of loco's and did not get round (i.e. forgot) to check it.  Now done and it would not work, even on DC??

Did and decoder CV check and reset CV29 from 02 to 38 so as to 'run in' on the Analogue circuit.  However still would not run DCC, checked again and noted it said it was a 'class 15' decoder??  I did a force set to Hornby steam (CV7) and set 001 which it then worked.!!!  Not sure though that all the CV settings are correct for the J36.

Just had a thought after typing this that it probably had an incorrect TTS decoder fitted from new which givwn the time I have had it means that warrenty claim not possible but also thought on that Hornby do not seem to do a Class 15 diesel so why is there a TTS decoder with this setting???

I have ordered another J36 TTS decoder for fitting in another loco so I can probably answer most of what I have put above but still confused over the class 15 question??>

[Chrissaf]

Did a decoder CV check and reset CV29 from 02 to 38

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2 is a 'short DCC Address' configuration [Addresses 001 to 127]

38 is a 'long DCC Address' configuration [Addresses 128 to 9999]

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Using 38 for CV29 when actually using a 'short address' can be potentially problematic. If CV29 was originally 2 then 6 would have been the correct CV29 value to use. To correctly use 38 in CV29 for a long address also requires complimentary adjustments to the values of CV17 & CV18 & CV1.

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I suggest that you write 8 to CV8 to factory reset the decoder. This will set the DCC address to 03.

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Then check CV29 and set to 6 if factory reset to 2, then test on DC again.

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But note this, if Hornby have factory set CV29 as 2, then this was done for a reason. TTS decoders are prone to 'DC Runaway' and using a value of 2 (disabling DC operation) helps to eliminate this unwanted behaviour.

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I suggest that if the factory reset puts CV29 back to 2 that you leave it as 2 and test the decoder using your DCC Controller set to address 03. Only after the decoder is working correctly on 03, should you consider changing the address from 03 to something different.

[96RAF]

From your explanation it would appear you are using Railmaster to read and force reset the decoder.

Railmaster reads CV7 and looks this value up in their database, then loads the CV set for that refence. This does not mean the actual decoder is forced to play with those CVs. The actual CVs are locked into the decoder at the factory and all you can do is read them and change the values within published limits. Unfortunately you cannot change the value stored in CV7 to make it easier for rm to oick the right one.

 

As you have found by use of the CV7 drop down list you can pick a similar if not exact match when RM pulls up the wrong decoder, thereby loading a similar set of characteristics for your decoder. 

 

If using an Elite you can laboriously hand read all CVs and determine or change their values. If using an eLink you are restricted to how you can manipulate things by RM.

[JWRStation]

Thanks for the replies.  Received the spare J36 and fitted it to a T9 with small 'cube' as the large round hornby speaker would not fit; sounds better.

Checked all the readings and CV29 is set at 34..  Tried this one out in the T9 and ran correctly with all sounds working though I did have to program the functions manually as there isnt a hornby J36 TTS yet in the Railmaster directory...

Reset the J36 TTS decoder and all running fine with sound after manual setting up the DCC functions; amazing what a CV 8 can do.  Still not sure why originally it did not work in DCC though I am beginning to suspect finger troubly regarding remembering to set the address after a CV8...