I'm not an engineer, but I know a bit about how potentiometers work and have replaced several joystick modules on my 360 controller in an attempt to prevent "stick drift" (input being registered when the stick is in an untouched position due to wear and tear of the internal gimbal mechanism and parts or the potentiomters themselves). I have 4 different joystick modules from 4 different manufacturers, including the OEM joystick module that has stick drift issues.
After installing the latest Chinese version, which I find to be fairly high quality this time around, I've noticed on various joystick testing software that the idle position is not centered at 0,0. The joystick feels great and mechanically centers very well, but the center position is off to the bottom-left of center, which will require a 10 to 15% deadzone to ensure non-input when untouched.
Is it possible to calibrate this mechanically or through software, and does anyone know how the OEM manufacturer calibrates it? And no, Windows or Steam's calibration does not change this.
I've searched on the net and found a suggestion of installing trimmer pots, which sort of seems like it would work, but I'm not completely sure how they work. Would it modify the resistance value coming out of the joystick pots and how would one go about installing them on an OEM PCB? The joystick module is required to lie flat on the PCB with 14 through-hole solder points, so I'm not sure if it's even possible to somehow augment the resistance by installing something in-between the pots and the board's traces.
Anyway, I'm just shooting in the dark. I've probably learned far more about potentiometers than I've ever needed to, let alone how most of the joysticks sold are cheap Chinese knockoffs, but I am interested if there is some way of re-centering the pots or augmenting the output "data" with reprogrammed offsets. I'm on the verge of suggesting that Steam programs this into their custom controller configuration with a low likelihood of success.