my servis m6115s starts its washing cycle and then stops?

my servis m6115s starts its washing cycle and then stops after a few turns , i`ve called someone out who scratched his head and then charged me £55.00 for the privilage ! i`ve contacted servis who want £88.00 for an engineer to turn out and i`m a bit loathe to pay that and then find out it`ll cost a fortune to repair, when i could buy another washer cheaper, i wondered if anyone had similar problems and repaired it thenselves, i`m not bad with a screwdriver and i`m pretty handy about the house, so if its not too difficult i`ll try to repair it myself,with the correct guidance of course !! simon