stannah 260 running on its own , on the way up , now does not come down?

I have a stannah 260 , the wife released the controls , the stairlift went back upstairs on its own, now will not come down,, wound it down, again travelled upwards again, looked at the pcb , the green no 9 is flashing , also there is a yellow i think no 6 showing, what does this mean,
stannah wants £169.00 to come out, my son is good with electronics , would like to sort out the problem ourselfs, would be grateful for any help,