DaveAus Posted August 5, 2013 Share Posted August 5, 2013 Not sure if this is a DCC or RailMaster issue but I have a class 47 that is very temperamental with speed settings. At 15 mph cruise speed its ok but at little slow 16-24 it goes crazy at an excessive speed - at 25 it settles but is a bit slow. If I set the cruise at 15 and manually up it to 20 on the PC it's fine. Any ideas ?? Link to comment Share on other sites More sharing options...
geoff77 Posted August 15, 2013 Share Posted August 15, 2013 Have you set the decoder parameters of acceleration and decelertion on the loco's decoder? Link to comment Share on other sites More sharing options...
poliss Posted August 15, 2013 Share Posted August 15, 2013 What decoder are you using? Link to comment Share on other sites More sharing options...
DaveAus Posted August 15, 2013 Author Share Posted August 15, 2013 poliss said: What decoder are you using? At present the B 21 pin I did start with the Hornby Sapphire but the loco worked in a opposite manner would only go slow. Link to comment Share on other sites More sharing options...
Fishmanoz Posted August 15, 2013 Share Posted August 15, 2013 Can't give you specifics but suspect its likely to be something around CV settings and there are many to consider. For a start, is it only an RM problem or is it the same with Elite? Although, having set it up in RM as the particular Class 47 you have, then RM should have done the standard speed table, back emf and accel/decel settings for you, after which it will be the same no matter which way you control it. The other funny thing in this is that, with the possible exception of the 8249, it shouldn't matter what decoder is in there as they should all behave the same, all being to the NMRA spec. I also know there is a thread in the DCC forum, probably 12 months ago and maybe more, where someone gave detailed instructions on solving this sort of problem by a structured routine of adjustment of a number of CVs. I can only suggest you try doing a search in there on CV and see what you find. Link to comment Share on other sites More sharing options...
rpjallan Posted August 19, 2013 Share Posted August 19, 2013 You will probably find that if you remove the capacitors from the motor your problems will be solved. I have several of these decoders in both Hornby and B@CHM@nn locos and removing the capacitors has solved running problems for all of these. Link to comment Share on other sites More sharing options...
Michael_A Posted September 13, 2013 Share Posted September 13, 2013 would be interested to know if that cured it.... Link to comment Share on other sites More sharing options...
Fishmanoz Posted September 13, 2013 Share Posted September 13, 2013 Whether it fixes Dave's Class 47 or not, this is a well known problem. Put simply, the capacitors are low impedance at DCC frequency and so degrade the DCC signal between decoder and motor. Link to comment Share on other sites More sharing options...
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