I too have had a problem with a NewFitness machine, but it's a different issue. For some years now my machine works perfectly with the belt running at all speeds, and the platform elevating as required - the only fault is the display will not light up. The buttons on the display do still work though.
There are no loose connections and the speed sensor is in place.
When I turn the machine on the display flashes but then there is a click from inside the console and the display goes off.
Has anyone had a similar problem did you get it fixed?
The machine is a CS01
Andy W
September 2016