I bought a pair of used Xbox 360 controllers in good faith and both left analog sticks were really loose. They were so loose that the analog sticks wouldn't even re-center after being pushed in any direction. I only swapped out the joystick itself as potentiometers rarely fail. I reused the factory potentiometers that were in the controller. After the replacement everything worked perfectly. The stick was nice and firm and had full freedom of movement. I don't know how good the green potentiometers are as I broke them off and used the original parts.
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