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Hornby R8249 Head/Tail Light Issue when CV29 set to reversed


SmarTrains

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I have recently recieved a replacement R8249 Decoder from Hornby (the last one was fried).

When I place it in my loco (in my case a Eurostar with ExpressModels lighting kit fitted, it works perfectly, both directions, appropriate head and tail lighting.

When I modify CV29 from 38 to 39 (reversing direction), the lights are constantly in headlight mode, regardless of the direction of travel.  With the previous decoder of the same make and model, setting this value alternated the lights correctly when the direction changed.

I am consisting two power cars - hence why I need one in reverse, for some background.

I have reset the decoder to factory and tried this again, but the issue still persists.

I am yet to try yet another R8249 in this loco, but does this seem like a faulty decoder, or another CV that is not set correctly (and not being properly reset when the decoder is reset) ?

I must say, I have been less than impressed with this decoder, having 3 been "fried" or faulty, and now this issue. Tempted to put my Sapphire decoder in this model as they seem a bit more robust and reliable.

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I think we've seen something like this before and I think it was due to one bit of CV29 being set incorrectly.  Try reading back CV29 to make sure it contains the correct value.  What controller are you using and what consisting method are you using, eg basic or advanced

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Hi Rog,

This is using an ELink with RailMaster. CV reads back correctly as 39.

I am using the double header mode in RailMaster, however that is entirely irrelevant, the issue is on this loco in a stand-alone mode when CV29 is changed as indicated, before the consist/double heading is even established in RailMaster.

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R8249 does not support anything other than basic double heading, i.e. both locos are allocated a common consist address by the controller.

 

RM double heads in a completely different way in that the consisting is done in the software not in the decoder. If you have RM-Pro then you can reverse one loco direction in a consist.

 

In advanced double heading the consist info is held in each decoder Via CV19.

 

What you are doing is crossing your controls and it will never be right.

Rob

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Hi Rob,

 

With respect, forget the double heading. This issue is on a single loco in single loco mode where the CV29 first bit has been changed to reverse the direction. Previously this changed the light direction also, now it stays on headlight mode with this new decoder. The question is whether this is a faulty decoder, or if there is another CV which may not be set correctly - despite the controller being reset.

 

The info on double heading was only for background, and is irrelevant to this issue.

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This issue is on a single loco in single loco mode where the CV29 first bit has been changed to reverse the direction. Previously this changed the light direction also, now it stays on headlight mode with this new decoder. The question is whether this is a faulty decoder, or if there is another CV which may not be set correctly - despite the controller being reset.

Value 39 as you say should be correct as it gives reverse direction, 128 speed steps, simple 3 point speed curve, DC running and long loco address.

 

You say if you drop the reverse the lights and direction then match OK. I know the decoder has to look at the speed curve to establish correct lighting logic so you may want to try value 55 which will use the complex speed curve, although you cannot adjust it manually on an R8249 decoder. If you don’t need DC running then ditch that also and make it value 51.

 

Rob

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There was much chat on a similar tack about Class 20 TTS diesels used in reverse face consist on another forum and the best idea was if it was always be going to run about face then swap the motor leads over was the simplest way round it. Much the same as you would cross wire a dummy HST or Pendo lights for instance. My article on Class 395 lighting uses this method.

Rob

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Gentleman, I appreciate you are trying to help, but you may be overthinking this issue.  I am happy to experiment with various ways to do the double header/consist at a later date. Back to the actual issue:

 

On a single loco with CV29 set to 39 or 35, the direction reverses fine, however the lights do not change from headlight to reverse light. Removing this setting, the lights function correctly.

 

The same loco functioned correctly before with another decoder, so I am going to put this down to (yet another) faulty R8249 decoder.  I have another two still in the box so will swap one out and see if the behaviour is resolved.

 

Re: 51: I don't think I need a Speed Table on this decoder - which doesn't actually support this function anyway, and I never needed this previously for directional lighting to work.

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It is looking like a duff batch, but there is one thing I forgot to ask and that is is there a coloured spot on the main chip on the R8249 (e.g. white, blue, yellow, red or none). If there is a spot is it in the centre or to the corner of the chip and is it a small or large spot.

This would help tie down the revision state of the decoder.

Thanks Rob

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It is looking like a duff batch, but there is one thing I forgot to ask and that is is there a coloured spot on the main chip on the R8249 (e.g. white, blue, yellow, red or none). If there is a spot is it in the centre or to the corner of the chip and is it a small or large spot.

Hi Rob,

 

3 of these decoders shipped to me in the last month directly by Hornby repairs - all have a large blue spot in the middle of the IC chip.  I have tested two which both have this issue, the other is still sealed in the pack.

 

Cheers,

Scott

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They are original issue v1.3 circa 2008 NMRA compliant. Generally OK. Later versions fixed a DC running problem (DC loco had to be stopped before it would reverse direction) and had a smaller blue dot in the corner of the chip and even later version had no coloured spot. The latter has improved readability with other make controllers. No real change to DCC functionality.

Rob

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If anyone is having similar problems with directional lighting and an R8249 please read,CV7 and provide the value (probably 132 as 133 seemS OK).

This may be similar to the early TTS class 37s that had swapped directional lighting problem from years ago.

Thanks  Rob

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I'm guessing next steps are to log these issue with Hornby?

 

As these were provided as replacements to faulty decoders, it's pretty disappointing that I will now have to have them replaced again. The $30 AUD return shipping cost to the UK makes this almost uneconomical.

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