rollers not engaging on one side when you try to engage just goes to off again if a power touch mover there is a safety mechanism built in.in behind the roller is a split pin this has shored of and will be in 2 pieces,this needs to be tapped out top to bottom and a new pin inserted but it is a fiddly job as one has to align the slots up, we find a piece of thin cord helpful to place through while removing pin.this holds it in line.the pins are available from power touch.the pin is located in line with the hex shaft.