Joysticks wont move up or down

I have a ton of Atari joysticks that will move left and right but not up and down and cant figure out why... I know its none of the systems I have tested good controllers on 5 systems I plan to sell with no issues. Any ideas why I can only get them to move left and right and not up and down? Even the fire button works as well. I am at a loss. I have about 14 controllers that are doing this.