Potentiometer burning?

One of our potentiometers was giving weird values today (it wouldnt go past 300 or below 150 no matter how much we turned it). So i took it out and it smelled like burnt plastic, and the middle part where the axle goes in was a light shade of gray. Its supposed to be white. Has this happened to anyone? These are brand new potentiometers as well and the “stoppers” inside the potentiometer are not broken.

I can’t speak for anyone else but I have basically stopped using potentiometers for their unreliability… I am sure @antichamber can tell you about broken potentiometers too…

Pots are indeed prone to breaking, and it is always recommended to have a bunch of spares. However their accuracy is still unmatched by anything else and thus I continue to use them for my dr4b, chain bar, and auton selection.

Values like you have described means that the potentiometer is either disconnected or broken, check your wires and if there are no issues there then change your potentiometer.

I think you have wired in incorrectly. You can imagine a potentiometer as a voltage divider formed by 2 resistors with variable values. In the middle, both resistors are the same, say 5kOhm. Near the end of the working range, one is the full resistivity (10k), while the other is almost zero.
Now consider the cortex analog port pinout: Black is ground, red is +5V and white is the measured signal. Thus a potentiometer has the voltage divider’s central tap connected to the white wire. If you get a 3-wire extension and plug the potentiometer in the other way, see what happens: One of the variable resistors will be between signal and ground, but the other will be accross 5V and ground.
Now, as you turn the potentiometer towards the 5V end, the resistance, now applied directly between 5V and ground, decreases towards the zero. Guess what happens if you apply strong 5V power supply directly accross a low-value resistor - high current flows, heat gets produced, smoke and burns might follow…

Yeah, I checked how it was wired and it was indeed plugged in backwards :P.