Castle Posted July 6, 2014 Share Posted July 6, 2014 Hi All, I have just fitted a Gaugemaster Opti DCC25 Decoder into my quasi kit built 1361 class saddle tank. On DC it was a smooth runner all the way through the power band. I have soldered in the chip and as we go up through the speeds, it crawls along quite nicely, then judders a bit then leaps off at 400mph! I am using a Z21 controller on iPad if that helps. I am fairly computer and electronic savy but this is the first DCC decoder I have fitted. What have I done wrong? Is there a CV I need to change? Help please! Thanks in advance. All the best, Castle Link to post Share on other sites More sharing options...
Vonzack Posted July 7, 2014 Share Posted July 7, 2014 Hi Castle, There are a couple of things to try. First turn off Back EMF if the decoder is capable of it. It can sometimes produce weird results with loco's when set to factory settings. If that doesn't solve the problem, then you need to see if the decoder is set to use a speed curve. If it is, then check that the speed curve doesn't have a large step in it making the loco jump to a higher speed. If it isn't, then there are 3 CVs which define the Min, Mid and Max volts to send to the motor, based on the throttle settings. Set these all to zero which is default. Allot of people on the forum use a piece of software called JMRI, which is free and comes with an excellent user interface for setting the various CVs of your decoders. You might want to look into getting a hold of it if you are going down the DCC route, it saves allot of time. Cheers, Mark. Link to post Share on other sites More sharing options...
RMweb Gold RedgateModels Posted July 7, 2014 RMweb Gold Share Posted July 7, 2014 I'd turn off DC running first, it may be that your controller is putting out a non-standard waveform at times that the decoder is thinking is DC not DCC - so it runs off at full power you need to look at cv29 - there's a handy calculator here http://www.2mm.org.uk/articles/cv29%20calculator.htm Link to post Share on other sites More sharing options...
Phil S Posted July 7, 2014 Share Posted July 7, 2014 Have you tried simply resetting the decoder by writing 8 to CV8 (in most cases .... some decoders have other options - particulalrly for partial resets) Have you ensured that none of the functions are interfering - that any unusued connections cannot short when running. Then, as suggested, JMRI s/w is the pleasantest way to program, as it is by ticking boxes, and having a speed graph displayed - if you are using that part. The graph would help show any anomoly from accidental programming too. Admittedly it takes time to read in all the data! A Sprog is a convenient way of having this as a separate dedicated setup. Link to post Share on other sites More sharing options...
Castle Posted July 7, 2014 Author Share Posted July 7, 2014 Hi Phil, Redgate & Mark, Thanks very much for the advice - I am a bit new to all this so the ability to pick your brains remotely is a massive help! I got back late from work today so I will re-read the manual for the decoder tonight and with luck put it practice tomorrow. Further updates as they happen... All the best, Castle Link to post Share on other sites More sharing options...
Castle Posted July 13, 2014 Author Share Posted July 13, 2014 Thanks Dutch! I have been uber busy at work this week and the thought of attempting the programming without prior experience when getting home was a bit of a no - no... I was fiddling with bits of a Castle (12":1' scale) yesterday but today looks good to go! Reports of updates will be posted as they occur... All the best, Castle Edit: I have the manual already - cheers! Link to post Share on other sites More sharing options...
Castle Posted July 13, 2014 Author Share Posted July 13, 2014 Good news! Turning the back EMF from naturally on all the time to a function button did the trick! A further question though, it doesn't matter whether the back EMF is on or off with the function button (I chose 12 but I don't think its important), the loco doesn't do the speed jump thing but if I turn it back to pure on the jump is back. Any ideas why this is? Many thanks for all the help thus far! All the best, Castle Link to post Share on other sites More sharing options...
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