Installing R8249 Decoder in 0-4-0 Loco

[Pedro48]

Hi

I am new to model railway and have set up Railmaster on my track and it is working well.

I recently tried to install a R8249 decoder in a 0-4-0 loco foloowing instructions on the standard 0-4-0 installation. However Raimaster does not see the decoder and I get CV values of 255. I unsoldered all connections and the motor works fine on a 9volt battery, but when I connect the decoder the motor does not operate even when connected directly to 9volt battery.

Could I have killed the decoder during installation?

[Chrissaf]

All CV values reading 255 means that RailMaster cannot detect the decoder as being present. I take it that you are putting the loco on a separate programming track piece directly connected to the PROG A&B output of your RailMaster track interface. If you are, then can you read CVs on another different loco to prove that is working. If that proves OK, then inspect your decoder installation preferably with a digital multimeter set to measure resistance and look for either a short circuit across the wheels or an open circuit between the wheels and the red / black wires on the decoder.

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TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

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See also – further TIPs on how to get the best user experience from this forum.

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

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[Pedro48]

All CV values reading 255 means that RailMaster cannot detect the decoder as being present. I take it that you are putting the loco on a separate programming track piece directly connected to the PROG A&B output of your RailMaster track interface. If you are, then can you read CVs on another different loco to prove that is working. If that proves OK, then inspect your decoder installation preferably with a digital multimeter set to measure resistance and look for either a short circuit across the wheels or an open circuit between the wheels and the red / black wires on the decoder.

.

TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

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See also – further TIPs on how to get the best user experience from this forum.

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

.My other loco, Flying Scotsman works fine, I have a separate programming track attached to the PROG output and the main track is isolated. All connections appear ok and I unsoldered and resoldered several times

 

 

[Chrissaf]

Please follow my advice given in my initial reply and refrain from using the 'Blue Button', this button is not a 'Reply to this post' button.

 

A visual inspection is not conclusive, you will really need to use a meter to prove the fault. Digital multimeters can be sourced cheaply on ebay for less than £8 delivered. Note that the underlined red text is a clickable URL link.

 

Your other FS loco works fine you say .... but can you read the CV values of it on the 'programming track' without issue? Your phrasing could mean that it 'works fine' operationally on the main track, but that doesn't answer or confirm the question I asked regarding CV reading.

 

Read TIPs 1, 2 & 3 in my posted TIPs page (see bottom link in my original reply) regarding extricating the text cursor from within the buff quote box.

 

 

[Pedro48]

Hi Chris

I used my multimeter as suggested. Have a complete circuit from the wheel to the black wire and from the other wheel to the red wire through the caoacitor. There is not completed circuit through the decoder ( red to black, to grey, to orange, black to grey to orange, orange to grey) The decoder seems to be compromised. If that is so can I use a 4 pin decoder ( R7274) or try another 8 pin ( R8249).

I programmed the Flying Scotsman on the programming track through the PROG output. All CV's were read and correct. Although the FS was DCC ready and the R8249 just plugged in.

Hornby products are difficult to obtain in Australia and hopefully will be available later this month.

[Chrissaf]

...from the other wheel to the red wire through the caoacitor.

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Presumably caoacitor means capacitor.

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You say the electrical route path is from the wheel through the capacitor to the red wire connection on the decoder.

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If that is true, then remove the capacitor. When a decoder is installed the signal path from the wheels must be direct to the decoder red and black wires. No other components must be in the circuit.

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Chances are, what you are calling a capacitor (if it was originally in series with the motor before you started to convert it) is in fact a suppression inductor and not a capacitor. Capacitor suppression components normally go across the motor terminals not in series with them, it is inductors that go in series. A series wired inductor will act as a brick wall to a DCC data signal and block it completely and most definitely must be removed. If it is an inductor that is in series, then it is no wonder the controller cannot detect the decoder being present.

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Maybe this generic decoder wiring schematic will assist you. It is always beneficial to add a socket as part of a non DCC Ready loco conversion. You can buy suitable sockets with wires attached for this task on eBay. Having the socket makes diagnostic testing and decoder replacement so much easier.

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/media/tinymce_upload/fe2caa0c94f307888e61c4090338ff8f.jpg

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Or if you go down the 4 Pin Decoder route. The 4 Pin Male Header is a standard Dupont 2.54" pitch product that comes in strips that you cut to length required.

 

4 Way Male Header.

/media/tinymce_upload/6099b24f67d5f139894283e6807d805d.jpg

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[Pedro48]

Thank you for your help and advice.

I have tried everything suggested and Railmaster still cannot read the decoder, I must have killed it when installing it. I have been told that some DCC Fitted locos will be available later this month, I will get one of those, less stress and anxiety.

Thank you once again.

[Pedro48]

Hi once again. I finally obtained the R7274 4 pin decoder, I installed it using your diagram and programmed it and Railmaster read the CV's and all apeared to go well.

However when I placed it on the main track nothing happened. During the programming process Railmaster stated that the loco was not listed in the database. It is from the Highland Rambler set (R1220) which is not listed in the Railmaster database, I tried to identify it as a Pug that was listed in Railmaster.

Do you have any ideas or am I wasting my time.

[Chrissaf]

There is nothing in RailMaster to stop you adding any loco you like from any maker you like. There is absolutely no mandatory requirement for any loco to be included in the RailMaster locomotive database. The function of the database is to be a 'time saver' when adding a Hornby loco to save time having to enter all the data manually. The other function of the RailMaster database is to set the 'scale speed' parameters for known database locomotives. But again 'scale speed' isn't a show stopper for adding a loco to RailMaster and can be considered an optional 'nice to have'.

 

To be sure, I would need to be 'looking over your shoulder' to see exactly what you are doing and how you are doing it. But I suspect that you are trying to follow the manual instructions for adding a database recognised locomotive, when in this instance it would probably be best to use a different method based upon a 'loco not in the database' method, which is not specifically documented in the manual.

 

I have written several tutorials on different aspects of using RailMaster, I suggest you adapt my tutorial on 'Manually adding a Loco to the RM Database' to add your loco. Note the the tutorial is written for a 'sound loco'. As your decoder is not 'sound' then just ignore the 'sound' related steps.

 

Manually adding a Loco to the RM Database.

https://www.hornby.com/uk-en/forum/r3459tts-decoder-not-recognized-23469/

 

For additional information, read the following thread,

 

Full description of the ‘Locomotive Settings’ screen in detail.

https://www.hornby.com/uk-en/forum/changing-cruise-and-shunt-speeds/?p=1

 

Another tip, if you have the 'CV Reading / Writing' screen open. Double click the CV7 entry and a pull down list will appear, allowing you to manually select the actually fitted decoder. If the R7274 is not listed, then select the R8249 as both these decoders are virtually the same.

[96RAF]

Usually RM picks up TTS decoders and says they are R8249s.

Double click on CV7 and select R8249/R7274 from the drop down list, which will load only the CVs applicable to that basic decoder. RM will then continue to read those CVs.

255 can mean a CV is set at max value but more often than not it means that RM is not reading  the decoder.

If  you are using an eLInk with RM then you are stuffed, buut if you have an Elite then try reading back in stand alone Direct programming mode rather than through RM.

The reason you can’t fiind Pug or any other 0-4-0 in RM database is because none of them are DCC Ready or Fitted from the factory.

[Fishmanoz]

Pedro, it is not difficult to by Hornby products in Oz, you order them from the UK. You can do it on the Hornby site but the prices will usually be higher than elsewhere and the postage very expensive.

 

A couple of reliable suppliers with good prices are Hattons and Rails of Sheffield. 

On your problem, using the standard installation guide, you leave the capacitor across the motor in place.  Remove it, it's not needed for DCC, and they have been known to go faulty. You would get your symptoms if it is short circuited. 

[Pedro48]

I finally got the loco running following your instructions. it runs okay but sometimes slows down or stops. I will persist and buy another 0-4-0 loco when they become available in Australia. Stocks are now starting to trickle in. Thank you for your help, I am learning more about DCC every day.