JRK 12v12: Red feedback curve is jittering

Dear All,

at the moment I have 4 JRK 12v12 boards installe on my rig:
2 for my 2 DOF seat and 2 for my integrated G-Seat.

The problem is that one of the JRK boards is not working properly: The red feedback curve is jittering so much, that it is not even possible to configure the board.

Here is a screenshot of the JRK config utility with the feedback curve:


All other 3 JRKs are working perfectly.

What I did:
I connected a different JRK with the pot and motor of the non-working board. Result: Works correctly.
That means it is not a faulty pot and not faulty wires.

Then I even bought a new JRK board and corrected it. Same result: Also the new JRK behaves in the same way.

So either both JRKs are defect (maybe because of some mistake I did by myself), or it is a configuration problem.

Did anyone of you ever xperience something similar?

Thanks a lot for any hint,
Markus

@noorbeast: Here are screenshots of my settings:




I have also added the exported settings file.

Yes, that's right. And that's my problem: I cannot do this due to the jittering.
I can set the "max" value, because on this end the curve is not jittering that much. But when I turn the pot for reaching the "down" value, the curve starts jittering and jumping from one end to the other, so that it is impossible to set the value.

Thanks, @noorbeast!

I already tried 4 USB cables, and yesterday I installed the latest firmware. (Maybe it was already on it before, because it hasn't changed for some years.)
I changed the samples to 512 when I compared the settings with those of a working board.

Tonight I will follow your recommendation to reset the settings to their default.

Unfortunately, reset did not solve the problem.

Yes, I tried a different pot yesterday without success.
Today I dismounted the JRK and a pot from my rig and just did a minimal setup: I just connected the JRK to the pot and to a USB port, i. e. without PSU and without motor:


Same result: The curve was jittering.

I have 2 JRKs and 2 pots separated from the rig, and I tested different combinations of them forth and back, and suddenly it worked.

Now both boards (still separated from the rig) work with both pots.

I have absolutely no idea what I did differently compared to my tests yesterday, and this is a bit frightening. However, at the moment the curve is perfectly smooth.

Next Saturday at the latest I will connect the JRK to my rig again and do further testing.

For now thanks a lot for all your thoughts and hints, @noorbeast.

Agreed. Maybe some tiny piece of metal sticked at the remaining soldering flux and I removed it when cleaning the bottom of the JRK. Otherwise I have no idea.
I really hope that from now on my 4th JRK will work as reliable as his three colleagues.
Then I am confident to finally have my rig fully functional next Saturday evening. In this case I will provide a report in my build thread.