zanussi w1242w wont do the final fast spin?

my zanussi washer dryer does everything apart from final fast spin ive checked variable spin knob,ive checked brushes,pump and all ok ,it happens with full load half a load or no load atall ,if i put machine on a slow spin cycle it spins but the main spin it blips up then stops it does this 4/5 times then dial moves to the end of cycle with clothes still wet Help me please..............