If wire is up side down static sound will be hear(plug in wire to wall outlet) ipod plays with head phones but not in docking station. ipod has a battery, is there a battery in the docking station?
problem solved, plugged in cord to wall outlet with the writing on the cord facing up, left unit plugged in over night and held down the + on the dock station for a few seconds and sound returned.
Unit had been unplugged for 4-5 days prior to the problem.