R8247 ACCESSORY DECODER PROBLEM

[Floyddy]

I am using 6 of these decoders on my layout to operate 21 Points Motors. All but one work fine, and have done so for some considerabletime, but for one reason or another that one will not retain the programmed numbers - in my case 69 - 72, for more than just a few days. Once re-programmed the Decoder will switch the points but, again, only for a few days. Has anyone else experienced this problem and does anyone know how it can be fixed? I assume a reset of the Decoder to the Factory Setting before it is reprogrmmed might help but can this be done and how? Any advice would be appreciated.

[Fishmanoz]

Return to Hornby for replacement, hopefully under warranty. 

 

There is is no reason to believe that returning the ports to 1-4, by reset or otherwise, will have any effect on your problem. 

[St1ngr4y]

Before replacing most of my R8247s with ADS's, I had a similar problem with one or two R8247s, and it usually occurred after a short on the DCC circuit. Then after advice on this forum, I fitted DCC suppressors which reduce any spikes caused by short circuits, which in turn can lead to an R8247 losing its programmed address.

Ray

[ff2nd]

I am using 6 of these decoders on my layout to operate 21 Points Motors. All but one work fine, and have done so for some considerabletime, but for one reason or another that one will not retain the programmed numbers - in my case 69 - 72, for more than just a few days. Once re-programmed the Decoder will switch the points but, again, only for a few days. Has anyone else experienced this problem and does anyone know how it can be fixed? I assume a reset of the Decoder to the Factory Setting before it is reprogrmmed might help but can this be done and how? Any advice would be appreciated.

 

Floyddy, what controller are you using, and what version of Firmware is it running?

[Chrissaf]

R8247's loosing their configurations is a well documented issue. I do not believe that the controller and firmware being used has any significant bearing on the issue. I had three R8247's which had been in storage for a year before being used, so were out of warranty. Everything was fine for months, then I had a 'short circuit event' on the track. After which, one of the three R8247's started loosing configuration for no reason every few days. Just as the OP has described. I too, did a CV8 factory reset first before re-instating the lost addresses.

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I too, just like Ray, fitted DCC suppressors. Things were greatly improved but the problematic R8247 still occasionally lost configuration. Just less often.

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Eventually, I just replaced it with a new one and have not had a problem since. I left the DCC suppressors in-situ as a 'protection' insurance policy.

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Note: sometimes the R8247 may just reset to factory default leaving the four ports as 1-4. In that scenario, one could just use it with the ports set to those particular addresses as their normal address configuration. So that when an unexpected reset does occur, no control is lost. But there is no evidence to suggest that just resetting to default will always be the case when the issue that triggers the fault occurs.

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In my case, my R8247 didn't always reset to 'default' addresses. More often than not, it reset the addresses as a 'negative' value address range (-3 to 0), so replacement was the only viable long term option. When the R8247 addresses went 'negative', the R8247 configuration was so badly corrupted that it wouldn't accept re-addressing without performing a CV8 factory reset first.

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PS - To manually reset the R8247 to the factory default. Connect the R8247 to your controller 'programming' output. Now just pretend that the R8247 is a loco. Using the loco CV programming function, write decimal value 8 to CV8. Note: this can not be done using the Hornby 'Select' controller as this controller does not support this type of CV programming.

[Floyddy]

Many thanks to the four of you who have kindly responded to my post regarding the problems I have been experiencing with one of my Accessory Decoders - R8247. Sorry I haven't responded to you individually - got callled away on business suddenly, but hopefully you will all see this post.

To Fishmanoz. Sadly, it is out of guarantee so if it needs to be replaced I'm going to have to pay for it.

To Ray. I hadn't given any thought to the problem arising after I have a short on the DCC circuit. This is a very real possibility and I will monitor closely. DCC supressors may well be the solution. Any ideas where I can get them - I live on Guernsey in the Channel Islands and I do not know if my one local model shop would have them. Presumably the suppressors are wired into the lead which runs from the Decoder to the Rail Connector?

To ff2nd. I am using an Elite controller and Version 1.41 Firmware.

To Chrisaf. A very comprehensive response for which I am grateful. Perhaps a Factory Reset and then re-programming of the address to 69 -72 coupled with the fitting of a DCC suppressor. Replacing the Decoder may have to be the final solution and I guess you would, again, recommend the fitting of the DCC supressors.

Thanks again guts

Malcolm

 

 

 

 

[Chrissaf]

Malcolm,

With regard the DCC Suppressors. You can buy them ready made from DCC Concepts (although I replaced mine bought from DCC Concepts with home made ones because I didn't like how hot they got - see comment later below). But they are so simple to make and a lot cheaper than buying ready made. Suppressors are also referred to as RC Filters and / or Snubbers.

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The Suppressor goes across the 'track' or DCC BUS. Or in your case, physically near to where the R8247's connect to the DCC supply. The Suppressor is made up of TWO components. A ceramic disk capacitor of 0.1 uF (micro farads) with a voltage rating of at least 35 volts (ideally 50 volt rating to be belt 'n' braces) IN SERIES with a resistor of AT LEAST 0.5 watt rating with a value between 100 and 150 ohms. This resistor will get very hot to the touch, so personally I would over-spec the resistor and make it a 1 or 2 watt resistor. A ceramic disk capacitor is not voltage polarity sensitive, so the Suppressor can go across the DCC supply either way round.

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More information can be found here and here.

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EDIT: If you don't have a DCC BUS and your six R8247's all connect to the track via their own dedicated track power clip. Then you could modify the connections slightly. Use just one track power clip connected to a 'screw terminal strip' under the baseboard. The six R8247's then wire in parallel into the terminal strip. The terminal strip doubles as somewhere to connect the Suppressor across the DCC supply to the decoders. Job done.....

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PS - Don't 'heat shrink sleeve' the resistor (as DCC Concepts have done) the heat shrinking doesn't help the heat dissipation.

[Gearoid]

 This also happened to one of my decoders recently, had to re-program regurlarly until it eventually gave up. Currently back with Hornby. Waiting for a replacement

[NigelB]

Hi. I am looking for some help with an R8247 accessory decoder currently setup to 4 surface point motors. My son accidentally reprogrammed his trains on the main track and we had to reset each in turn with the programming track. The point controller is no longer working so I believe it also needs reprogramming. I am looking for some advice how to do this. Presumably the trains need to be removed but do we need to only leave one set of point wires connected then connect the other 3 point motors? When we come to connecting a second point controller do we need to disconnect the original decoder, calibrate the new decoder with one set of points connected then add the other points and reconnect the original point controller? Instructions supplied are not clear so help would be appreciated. Thanks.

 

 

[Chrissaf]

From what you have described it sounds like you are using the Hornby 'Select' controller. Because the 'Select' does not have a separate 'programming' output (other controllers do) there is a slightly different process to follow. If you could confirm what controller you are using, then it would be easier to give specific guidance.

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In essence you must isolate and configure each Accessory Decoder individually, one at a time.

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Nigel, too late now. But it would have been preferable if you had started your own thread with your question as a new topic, as your question is not quite the same as the question raised by the original poster (OP). By hijacking this existing thread your question may not be seen by so many people and you will get potentially fewer direct responses to your issue.

[Fishmanoz]

Nigel, first, welcome to the forums, second, Chris is right about starting new threads for new problems and third, you are correct.  When you want to program something, it must be the only thing connected to the controller or track.  And the easiest way to do this is to have a separate piece of track that you connect to for programming each thing you want to program (known as the programming track), so avoiding having to remove everything else from your main track.  There's nothing to stop you using your main track for programming, it's just inconvenient always having to remove all other locos and accessory decoders.

 

Finally, for most accessory decoders these days, that includes the R8247, you don't need to have a point motor connected to it at the time, on port 1 or any other port.

 

PS.  As I've described it, it doesn't matter whether you are using a Select which doesn't have a separate programming output, or Elite or eLink which do.  You just connect whatever is the correct output from the controller to the programming track, and for Select this is the only output.