changing CVs on r8249 decoders

[heuston]

Hi, I have a Hornby r8249 decoder connected to a set of lights I picked up, for a Hornby 08 0-6-0 diesel shunter. I have all the wires connected up properly to the lighting unit.  The two white lights work ok, and change in reverse and forward. One of the red lights comes on in F1, the other comes on in F2, but only momentarily. The white light for the cab does not come on at all. I know that F2 is set for short blasts on the horn . Is there a way I can change the CVs on the decoder to sort this problem.

Thanks,

Joe. 

[Chrissaf]

I know that F2 is set for short blasts on the horn.

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Firstly a R8249 is not a sound decoder so it is impossible for it to sound a 'Horn' on any function number.

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I have all the wires connected up properly to the lighting unit.

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I wish I had a £ for every-time someone says I have wired it correctly. No disrespect, but let's be honest, if it was wired correctly then it would be working.

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One of the red lights comes on in F1, the other comes on in F2, but only momentarily.

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Is sounds as if you have wired up the red lights incorrectly. The red lights should go on the 'white' and 'yellow' wires and be automatically reversed with the white lights via F0 depending upon the direction to loco is travelling - see schematic below for details. The only reason for not putting the rear red lights on the 'white' wire is so that you can control them in a loco prototypical manner. That is to say they do not show the rear red lights when the loco is hauling rolling stock behind it in the forward direction.

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F1 and F2 are AUX functions. F1 is associated with the green wire and F2 with the purple wire. See the schematic below for the recommended R8249 wiring configuration

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/media/tinymce_upload/dff3d0c7a34994f3918d1edc264a4c14.jpg

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The white light for the cab does not come on at all.

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What colour wire is the 'Cab Light' connected to?

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Is there a way I can change the CVs on the decoder to sort this problem.

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The R8249 is a very basic decoder and does not support function button mapping. The only solution is to re-wire the lights following the schematic I have provided above.

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I suggest

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Putting the Front white LEDs on the 'white' wire.

Putting the Rear white LEDs on the 'yellow' wire.

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Then assuming you want the Front red lights to come on when the loco is in reverse, you put the Front red LEDs on the 'yellow' wire.

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The above will be enabled or disabled via the F0 command and change colour with respect to loco direction.

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If you also want the Rear red lights to be switchable in a prototypical manner then you put the Rear red lights on the 'green' wire and switch them on and off with F1. Else if prototypical operation is not a requirement, put them on the 'white' wire with the front white LEDs.....see my schematic.

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This leaves the 'purple' wire for the 'Cab Light' switched on and off by F2.

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Remember the light LEDs should have current limiting resistors in them (as shown on my schematic) and all connect to the positive blue wire on the positive side of the LEDs.

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With regard the comment ".....other comes on in F2, but only momentarily." please tell us which DCC controller you are using as this has a bearing on the momentary operation?

[Howbi]

When the R8249 decoder is wired up correctly the yellow wire operates the red lights, the white wire operates the white lights, the blue wire is the common return. Then pressing Function 0 turns the lights on which should comply with direction of travel.

Function 1 only operates a device connected to the Green wire (&Blue return).

Function 2 only operates a device connected to the Purple wire (&Blue return)

You could have a cab light wired up to the Green wire which would be controlled by F1

 

The R8249 is not a Sound decoder so your comment about F2 set for short blasts on the horn is incorrect. That may apply to the Hornby TTS sound decoder.

There is no need to change any CVs if your wiring conforms to the accepted standard.

 

PS Chris was faster this time.........HB

[Rog RJ]

What controller is the OP using?  Some controllers have F2 set to only give a momentary action instead of latching and F2 may be labelled "Horn/Bell"

[heuston]

Thank you gentlemen, I use the Gaugemaster Prodigy Advance, so F2 is used for short blasts on the horn. The decoder is connected to the lighting unit as per instructions. I know that the r8249 is not a sound decoder. Perhaps I should have made that clearer earlier. I have included an image of the decoder and lighting unit. Appreciate your replys. Regards, Joe./media/tinymce_upload/ddf4d05466b11d39b5adfe24eb715b05.jpg

[heuston]

Thank you gentlemen for your replies. I use a Gaugemaster Prodigy Advance.  F2 on this controller is set for momentary action. I know that r8249 decoder is not a sound decoder. Maybe I misled you earlier on that. The lighting unit has the usual coloured leads, white, blue, red etc. And the instructions tell me to connect these to the corresponding colours on the decoder, which I did. I tried to upload an image of the lights and decoder, attached to each other, but for some reason I was unable to. I think I have to get clearance for this. Can you tell me how to go about this. I would make things a lot clearer. 

Thanks again,

Joe.

[Chrissaf]

Regarding posting an image.

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Read TIP number 8 in my forum tips page.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

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Note that images posted today, won't appear until Monday at the earliest if they are held back for administrator approval as ComMods can not approve images.

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You keep on using the term "Lighting Unit". In my first reply, I assummed this is what you were calling the DCC R8249 decoder.

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What exactly is this "Lighting Unit"? Please explain.....

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If it is a third party product purchased to modify your loco, then give us an Internet link for this product so that it can be researched. No disrespect intended, but if you only give us half the detail, then you cannot expect more than half an answer.

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Us understanding what this unit is, is crucial to being able to offer you appropriate advice.

[heuston]

Thank you Chrissaf, The product in question is a DDC/H08 DCC head and tail lights for Hornby class 08/09. The link is www.expressmodels.co.uk. I was afraid to give this link, in case it was against the forum rules.

Thanks, 

Joe.

[Chrissaf]

There is no equivalent Hornby product that does the same thing. So there is no issue posting a web-link to non competitive products from third parties. The forum rules just forbid aggressive promotion of other products. Discussion of other products is totally allowed and OK.

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But unfortunately, Express Models do not post the installation user guides that can be downloaded. Thus knowing what the product is, is not much help on this occasion as the Express website provides no further information about the product at all, that I can find.

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Do you have a scanner, can you scan your printed instructions for this product and post them as an image either .PNG or .JPG file format (not .BMP or PDF). This would be much better than a photograph of the product itself that you said you would like to post.

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I have used Express models myself and found them very helpful. Have you telephoned them and discussed your issue with them over the phone. The ability to have a verbal 'one on one' conversation with the supplier is likely to hone in on your issue solution far more quickly than a text based back and forth dialogue with forum members who may not be 100% familiar with the actual product.

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F2 Momentary Function issue.

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Now that you have told us that the controller is the Prodigy Advance

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This other forum web-page indicates that the Prodigy handset cannot reconfigure the F2 button for latching operation. The solutions offered, all suggest remapping the F2 function within the decoder to another unused function button that is latching on the Prodigy controller.

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Fine in principle, but the R8249 decoder is too basic and does not support function button mapping (this was stated in my orginal reply). So since you can't fix it at the Prodigy controller end, your only other solution is to replace the Hornby R8249 decoder with a more functional four function decoder that does support function mapping. There are many brands that do with similar pricing to to the R8249.

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[jane1707819582]

Thank you gentlemen for your replies. I use a Gaugemaster Prodigy Advance.  F2 on this controller is set for momentary action. I know that r8249 decoder is not a sound decoder. Maybe I misled you earlier on that. The lighting unit has the usual coloured leads, white, blue, red etc. And the instructions tell me to connect these to the corresponding colours on the decoder, which I did. I tried to upload an image of the lights and decoder, attached to each other, but for some reason I was unable to. I think I have to get clearance for this. Can you tell me how to go about this. I would make things a lot clearer. 

Thanks again,

Joe.

Just check the lighting wiring colours they should be blue ,white and yellow ,your post suggests red is used ?

[heuston]

The instructions do no contain to much information, but yes I will be able to scan them, and forward them to you. I will get around to that later on this evening. Thanks for your patience.

Thanks,

Joe

[96RAF]

Express models instructions usually cover basic decoders and those with more functions.

For the basic decoder:

The front white and rear red lights wires in the kit are connected to the decoder socket white.

The rear white and front red lights wires in the kit are connected to tje socket yellow. 

Kit blue wire connects to socket blue.

 

For more functional decoders the front and rear lights at each end can be split and connected as individual wires to the decoder. I’m afraid I can’t remember the colours used without finding the instructions for those kits I have, but red and green spring to mind In addition to the usual white and yellow.

[heuston]

Scaned images as requested. Joe/media/tinymce_upload/3827d24c3fe3e9cd460ba2528780b462.jpg/media/tinymce_upload/32c9e42cc5b5ebe3090acefe7f7f81f1.jpg/media/tinymce_upload/5689d930eb2b9268679b1f02d6978bb0.jpg

[Chrissaf]

Thank you for the instructions as requested.

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After reading the instructions I have come to the conclusion (maybe an incorrect conclusion) that this lighting board is not fully compatible with a Hornby R8249 decoder. The lighting board seems to require the four functions of a four function decoder to be mapped to specific function numbers. The Hornby R8249 does not support function mapping.

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By default the Hornby R8249 maps the first function (white wire) and second function (yellow wire) to F0 on the controller.

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This lighting board appears (as far as I can see) to require the second function (yellow wire) to be remapped to F1 on the controller so that the white and yellow wires can be enabled / disabled independently and the yellow wire not auto controlled based upon loco direction The third function (Green wire) to be remapped from Hornby's F1 to a mappable decoder F2 controller button. The fourth function (Lilac wire) to be remapped from Hornby's F2 to a mappable decoder F3 controller button.

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Although the printed instructions have been useful, they did not include any schematics of the wiring solution. Instead the instructions rely on the reader comparing the written text to the actual product held in the hand. So since we can't see the physical product, the instructions are less helpful than perhaps they could have been.

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I believe you are best served with this query by talking it through directly with Express Models with a phone call. Describe your observed symptoms, point out that you are using a R8249 that does not support mapping (assuming my mapping deduction is correct) and see what they say.

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[heuston]

Thank you Chrissaf, Your detailed observations are much appreciated. I think my next move is to call in to my local hobby shop,they are always very helpful, and buy a different decoder. I will bring in a copy of your reply,  if that is ok with you. I would appreciate your suggestions on which decoder you think might work. I will let you know how I get on.

Thanks Again,

Joe. 

[Chrissaf]

I would appreciate your suggestions on which decoder you think might work.

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The clue is in the instructions.....page 2.....list item 12.

[heuston]

Thanks Chrissaf, The answer was right under my nose. 

Thanks,

Joe