i dont remember exactly...it's been a while...but shouldnt be much...i think just a couple of gear wheels, a magnet, and a couple of springs to provide tension. not really that difficult, just tedious to put back coz the pieces are so small...just make sure the magnet is put back the right way coz wrong polarity will reverse the direction of the antenna (i.e., IN instead of OUT). if ur gonna replace it anyway, might as well open it up, right?