Hi,
my machine had the same fault and seems to be quite common. What I did was remove the pcb behind the control panel buttons, its held on by several plastic clips and simply ensure the ribbin cable was making a good conection from this board to the programmer. My fault was either a loose connection or the pcb was not in the correct position either way, it now works perfect and only took 5 mins work @ no cost.
SteveMc electrical engineer
September 2008