Brand new decoders, purchased in UK and carried home to Michigan. Installed in two new loco's this week, on new track. Both run, but stop at random points on the layout, and sit with no control for 90seconds (always this period) then set off again at the same speed. Lights are still on during this period, so still powered up. I have two of them, different loco's displaying the same problem. Not returnable as the store is 3000miles away... Can you help?