Road Stone Posted February 25, 2010 Share Posted February 25, 2010 G'day All, I have the following issue: Three loco's one with a Bach 2 function and two with Bach 3 function decoders fitted, on start up Kangaroo hop or lurch very slightly and this continues at very low speeds. Accelerate a little and smooth running takes over. Each Loco (Bach Class 108/Hornby Black 5/Heljan 47) has a speed setting of 128 and acceleration level of 1. The usual things such as clean wheels/track/pick ups are in place. I don't have these issues with locos fitted with Hornby/Lenz/NCE and TCS decoders. Interestingly de-acceleration is perfect and a Class 40 with the same decoder does not suffer the same problem. I'm a little perplexed. Any suggestions would be gratefully received. I operate with the Elite. Cheers, Jerry Link to post Share on other sites More sharing options...
Suzie Posted February 26, 2010 Share Posted February 26, 2010 Jerry You say you get problems with Bachmann but not with Lenz, but the 2-function Bachmann 36-552 is a Lenz decoder. I have seen this 'Kangaroo' type problem with the Bachmann/ESU 36-553 decoder, where it has trouble decoding some packets. If your Elite has the ability to control a DC loco you should make sure that this is set to stop. Â Link to post Share on other sites More sharing options...
RMweb Gold Trevellan Posted February 26, 2010 RMweb Gold Share Posted February 26, 2010 Jerry, I have about 20 of the 36-553/4 decoders in use and would offer the following comments. First, you say that the acceleration is set to 1. Do you mean CV3? If so, I would increase this to 6 or 8. I have also found - confirmed by some fellow RMwebbers - that lowering the CV5 value can help to improve slow running. Link to post Share on other sites More sharing options...
smokebox Posted February 26, 2010 Share Posted February 26, 2010 You need to adjust CV54 and maybe 55 on the 3 function decoder. Probably reducing CV54 to 20 or 25 or thereabouts. These CVs adjust the amount of back emf. On the 2 function decoder, which doesn't have bemf, I'd try turning off the DC running capability in CV29 Link to post Share on other sites More sharing options...
Road Stone Posted February 28, 2010 Author Share Posted February 28, 2010 Thanks for the advice. I have changed the CV's as recommended and there is indeed a marked improvement. Just needs fine tuning for each loco. You can switch off the DC function on the Elite, which I have done, and as I did this at the same time as changing the CV's, am not sure which change improved matters most. Cheers, Jerry Link to post Share on other sites More sharing options...
Alcanman Posted March 2, 2010 Share Posted March 2, 2010 Hi, I have a similar problem with a Hornby Class 60 to which I have just fitted a Hornby R8249 decoder. The loco starts up on notch 1 on my NCE PowerCab and then proceeds to jerk and wobble eventually beginning to run smoothly at medium speed on notch 5 or 6. The headlights work fine and switch on and off. As I only have a small shunting layout, smooth slow speed control is essential. My 2 Bachmann Class 37s with factory fitted decoders run smoothly at all speeds on the layout. I am new to DCC and this is my first decoder fitting. Can anyone suggest a solution to enable my Class 60 to commence shunting on the layout. Thanks, Alcanman Link to post Share on other sites More sharing options...
StaffsOatcake Posted March 2, 2010 Share Posted March 2, 2010 Hi, I have a similar problem with a Hornby Class 60 to which I have just fitted a Hornby R8249 decoder. The loco starts up on notch 1 on my NCE PowerCab and then proceeds to jerk and wobble eventually beginning to run smoothly at medium speed on notch 5 or 6. The headlights work fine and switch on and off. As I only have a small shunting layout, smooth slow speed control is essential. My 2 Bachmann Class 37s with factory fitted decoders run smoothly at all speeds on the layout. I am new to DCC and this is my first decoder fitting. Can anyone suggest a solution to enable my Class 60 to commence shunting on the layout. Thanks, Alcanman Check how clean the wheels and pick ups are and also whether there is a good connections between the decoder chip and plug. I have had experience of the Hornby decoders and calling the wiring and soldering on some of them as flimsy is an over statement. Darn right shodddy is more apt as it easily falls apart. Link to post Share on other sites More sharing options...
Road Stone Posted March 2, 2010 Author Share Posted March 2, 2010 I have to say I'm completly fed up with the Bach 2 function decoder. Limited CV's and no BEFM means it is not suitable for the Black 5 it is currently in. The B5 struggles to maintian a smooth speed round curves and I guess this is the increasing friction on the large driving wheels which if the decoder had BEFM, then it would compensate by drawing more power? I've ditched it in favour of the El cheapo Hornby chip and as with all my loco's fitted with this decoder, can not complain. Very good slow running and much smoother performance. Cheers, Jerry Link to post Share on other sites More sharing options...
Alcanman Posted March 3, 2010 Share Posted March 3, 2010 Thanks, StaffOatsCake I've checked all decoder connections and wheels/ track are clean. Unfortunately no improvement in slow running. Alcanman Link to post Share on other sites More sharing options...
Brian Posted March 3, 2010 Share Posted March 3, 2010 Hi If you're 100% sure all the rails tops and all the locos pick-up wheels are spotlessly clean then... I would check firstly you're operating in 128 speed steps. Then.... Unfortunately the Hornby R8249 doesn't support many CVs and the Start voltage setting (CV2) is one of those not supported! I would try setting CV10 to 1 and retry the loco, then increase CV10 value by units of 20, from 1 to 20,40,60 and so on, trying the loco after each adjustment. CV10 default setting is a value of 128, which is its maximum setting. Also try turning off dc operation in CV29. Link to post Share on other sites More sharing options...
StaffsOatcake Posted March 3, 2010 Share Posted March 3, 2010 Thanks, StaffOatsCake I've checked all decoder connections and wheels/ track are clean. Unfortunately no improvement in slow running. Alcanman I can't remember which CV it is on the Hornby decoder as I have removed them from my locos because of the shoddy soldering. But when it worked it was good as I tweaked the decoder so that it ran really slowly in the loco it was in so it can be done. I am a confirmed NCE DCC user and have never experienced the kangaroo problem with any locos other than a Hornby 2-6-4 stanier tank, which I have put down to the sticking valve gear rather than a decoder problem Link to post Share on other sites More sharing options...
Alcanman Posted March 3, 2010 Share Posted March 3, 2010 Hi, Brian I've tried your suggestions but sadly there is no improvement. Thanks, Alcanman Link to post Share on other sites More sharing options...
Brian Posted March 4, 2010 Share Posted March 4, 2010 Hi, Brian I've tried your suggestions but sadly there is no improvement. Thanks, Alcanman Hi Sorry it didn't work - worth a try though! I would now ditch the Hornby decoder and buy something a lot better! Try a TCS. If the loco is DCC Ready (has an 8 pin socket fitted) then seriously consider the TCS DP2X-UK. Do Make sure its the 'UK' version. This is a Plug & Play decoder (no wires) and it plugs directly into the place occupied by the dc blanking plug and is about the same size. Its a nice little decoder Link to post Share on other sites More sharing options...
Alcanman Posted March 4, 2010 Share Posted March 4, 2010 Hi Brian, I had originally intended to buy the TCS decoder after reading good reviews in this forum but found the Hornby decoder available at a local shop. Although aware of the mixed reviews for the Hornby decoder I bought it to try my first attempt at at decoder fitting. Now wish I had bought the TCS. Thanks for your help, Alcanman Link to post Share on other sites More sharing options...
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