Hornby R8012/R8013 HM2000 replacement control potentiometer knobDo you have an HM2000 controller where the speed control is erratic? You may notice the "click" on the speed control doesn't happen until you've turned the knob part way around. This is a very common fault and we can replace the parts for you. The price includes fitting. You need to send us your controller and we will repair it for you. Please select either one channel or two channels from the list below if one of both of the control knobs is faulty.