C-stick Sensitivity/low range

[Kanelot]

I used a piece of homebrew Blargaman91 sent me to try to find out if my triggers were working, and instead I discovered that my C-Stick was having serious issues. It turns out that while my main joystick ranges from 128 to -128 on the Y axis and 128 to -128 on the X axis, my C-Stick appears to only go 90 to -70 on the Y axis, and a measly 50 to -50 on the X axis. Why is the sensitivity so low? This isn't normal right? Could this be due to poor soldering on my part, or a faulty stick


Here is a glorious wordless video demonstrating my distress.


https://www.youtube.com/watch?v=juzjuJ5wkVQ



All advice is welcome.

 

[vince]

take off the cap and try again?
Try the c-stick on a second controller if you have one?
If you still get the issue, it could be broken. I wouldn't know how to fix it.

 

[Blargaman91]

That's really strange. You should get about 0 to 100 on each axis of each stick.
If you can, measure the output voltage coming directly from the joystick on the X and Y axes of both the main stick and the C stick, which would be the middle pins here:

(ShockSlayer's diagram)

Just move it around while measuring the maximum voltages that come out of it.
Compare the C-stick's voltages to the main stick's, and if you see the C-stick's is significantly lower, I would say it's broken mechanically.

 

[Kanelot]

@vince

I took off the C-stick cap and replaced it to no avail. I would try the C-stick on another controller... if I had one. It's wired onto my controller board, and would be quite a pain to detach, buy another controller, open it up, wire that controller to my mobo, then wire the C-stick to it just to test it. Could I perhaps test it with my multimeter by measuring resistance on the x/y data lines when I move the stick around?

@Blargaman91

That diagram looks sweet. I'll give it a try in a minute. I will measure the voltage of the X and Y pins and get back to you. Thank you so so much.



@Everybody

I'm thinking that maybe poor soldering is the cause. I wired up my main joystick with lead solder and had great connections while the connections on the C-stick are mostly cold solders. Is this a possible cause, or is there no way that this could alter the x/y axis signal?

 

[Blargaman91]

Is this a possible cause, or is there no way that this could alter the x/y axis signal?

It's hard to say because that may just depend on what the GC controller does internally with a poor connection. I've seen it do some weird stuff, although I don't know much about that.

 

[Kanelot]

Used the multimeter, and sure enough, the voltage in the data line is lower in the C-stick. In fact, I found that the power line for the C-stick in general has a lower voltage! This would most likely be my issue, right? If my controller is supplying a voltage that is too low, naturally the potentiometers in the joystick are going to output too low voltages, right? I think this might be the issue! Could I wire the power line from my main joystick to the C-stick as well, and have it run off that? That seems to be outputting the correct number of volts.

 

[Blargaman91]

Yes, the joystick is meant to run off the same voltage as the controller. So you can feed it the same 3.3v line being used by the controller.

 

[Kanelot]

Problem solved! Thanks so much for your help, C-Stick works like a charm now. Glad I finally got this figured out: if I couldn't constantly rotate the menu during Melee, I don't know what I'd do.