Joystick Problems

Hi
I am having a problem with my vexnet joystick. The x axis of left joystick is giving an output of almost full power when it is in the center. I tried calibrating it multiple times, but that didn’t help. Then I opened it up and found that if I wiggle the plug on the main circuit board leading to the buttons on the top of the joystick I can sometimes get it in a position where the left joystick works properly. I found some white powdery junk around the pins on the plug, and I tried to make sure it wasn’t connecting any of the pins, but that didn’t help.
Does anyone have any advise?
Thanks

You might want to contact customer support on this one. It could be a manufacturing defect. The white stuff you see is probably soldering flux, which is a normal material used in manufacturing. I hope that helps.

support@vexrobotics.com

Probably a bad/cold solder joint.

Yeah, I kinda thought about suggesting they hunt down the disconnect and try to re-solder it but I figured that they would most likely just fry their unit and hate me forever. Better to turn it in for a replacement if they can.

Would a bad solder joint on the wires leading to the 7 and 8 buttons effect the functionality of the stick?

I doubt it. But any kind of flexing of the circuit board might close any hairline cracks/gaps in the solder that involves the joystick circuit you’re having trouble with. Cold solder joints (caused by soldering the connection at too low of a temperature) can look okay during casual inspection but can be infuriatingly difficult to track down because of their intermittent behavior - the break could be in a number of places so it takes probing the board with a multimeter, etc. but even then, the pressure of the probe can be enough to close the gap and make everything look okay at the particular spot you’re probing.

It does seem odd.

I had one bad joystick where I had to reflow the solder on the potentiometer for one axis. Perhaps you are flexing the board slightly when you move the connector. I don’t have a joystick or photos here at work to refresh my memory as to what connectors are inside and what functionality they have.

After reading your post, I glanced at the connections for the joysticks again and saw something. The far left pin (if the side of the joystick with with the five and six buttons is pointed away from you) of the x axis potentiometer of the left joystick seems to be bent up under the pot and not touching the circuit board at all. It seems that this is probably causing the problem. However, this still doesn’t immediately explain why wiggling the plug would effect its working. It is possible that I imagined I was effecting it, but it was actually just random. The detached pin could cause random changes in the output of the joystick couldn’t it? Doesn’t the controller chip need the third pin as a sort of reference point?