Move potentiometer thrustmaster hotas x, ( Resolved )

[federico]

Hello everyone , I'm not an expert of course, but something I understand.
Like you, I'm a fan of EEVblog , and I read that I recommend asking the questions here, here I am.

I have a ridiculous problem, which is costing me a lot of money.
simple:
I have a 5-axis joystick from the thrustmaster.
I want to use his electronics to create a helicopter simulation station done well. (ex: puma fligt simulator helicopter).

I decided to take one of the potentiometers and move it out of its original housing to create an external axis.
So, without making any changes,
I simply identified the original cables,
desoldered,
I pulled out the potentiometer
I sold them back to the pcb
Without making any changes.
Despite everything, as soon as I connect the joystick to the PC, the axis that I moved, moves by itself.
It works, but if I leave it to the es: 75%, he dances between 74 and 76%, and never stays still.
I already bought 2 joysticks, and both broken the same way.
But you can know what am I wrong

I think it's very easy for you.

I am attaching photos of what I have combined and the picture of how the project will be finished, I am trying to make the puma with 150 $ 

Thanks in advance.
Federico.

[jm_araujo]

The "dance" you're seeing is noise induced in the wires. By making the cable longer it turns into a sort of antenna.

If you can't make the cable shorter, the first solution would be to try and use a shielded cable, with the shield connected to the joystick ground.

[federico]

Thanks for your fast reply.

jm_araujo:
I used its original cables, without changing their length.
I only moved them out of the joystick.
You say I have to delete them and put es: a piece of USB cable?

blueskull:
To avoid this, I have unsoldered the wires from the PCB, without touching the Pot. Adding if I put a potentiometer taken from another working axis, the problem remains.

[sainter]

I would guess, maybe a bad solder joint when reattaching the cable.

[paulca]

If it's an actual potentiometer, they do that.  Especially after lots of use or if old.  This is why more expensive joysticks like the Thrustmaster Warthog that I have use Hall effect sensors instead.

There is a chance, the original contained a microcontroller to smooth the potentiometer values with a sliding window averaging.

Have you ever had a volume control on a HiFi scratch and fizz when you move the volume control?  Same thing.

[federico]

Thanks so much jm_araujo !! 

I connected the pot directly to the pcb and it worked fine, so I connected a piece of a shielded USB cable and I connected the shielding to the GND of the joystick as you indicated, problem solved !
Occasionally it flickers, but it works at 98%.
I used the same length of the original cable.

I believed that these problems were only there on great lengths, today I learned something new.

Thank you, thank you, thank you, thank you, thank you 

thanks also to everyone else for the help!

Bye bye

PS. I attach a picture with the links found on the internet.