Merlin The Wizard

HOORAY! After fitting (what I believe is) a Gaugemaster DCC25 Opti decoder (bought second hand with no instructions/packaging) the unit runs extremely well at low speed and also coming to a rest..... NO JUDDERING. Not sure if the Hornby R8249 is faulty or just incompatible with the CD motor. Thanks to all for your responses.

Thanks Barry 350851, I don't think it's a duff motor as it works sweetly when run in analogue mode. I'm going to try another (non Hornby) decoder to see what that does.

Hello all.... In order to give my Class 86 a bit of pulling power I decided to upgrade the Ringfield motor to a "CD" motor. The installation was very straightforward and I looked forward to a smooth running engine. The unit was already converted to DCC with a hard wired Hornby R8249 decoder. However at very low speed the train judders violently and if pulling coaches/trucks inevitably causes derailments, once speed is increased by the controller the juddering disappears. The same problem happens when the train comes to stop after slowing down. I complained to the supplier who provided a replacement motor but this has made no difference. I have tried adjusting "Startup Voltage", Acceleration/Deceleration rates via my Elite but I'm a little out of my depth. Today I have removed the decoder and returned the train to analogue and ran it my DCC layout as "Train 0" and it runs perfectly at all speeds. I'm not sure what the voltage rating of the motor is as there doesn't seem any markings relating voltage on the motor casing I'm contemplating borrowing another decoder from another engine but seem to remember I'd already tried this some months ago with no success. Any suggestions would be welcome. Thanks