I have tried over and over again, following the instructions, to get the garage door to stop just before the top and to go all the way to the bottom. I hold the black button in for a couple of seconds until the light slowly blinks. I then use both the black and purple buttons to move the door to the top position. Then I press the remote button and the door begins to move down, but usually just goes down about a foot and then snaps the door back to the top. How can I set the bottom stop, if I can't get the dang door to go to the bottom following the directions??? I can hold the purple button down and make it go to the bottom, but that just sets the bottom as the top, so the door won't go anywhere. I've gone up and down so many times. I've tried setting the force, but doesn't work either. Is there anybody in the Port St. Lucie Florida area who can get this thing going???