ST16 sluggish gimbal

[solder monkey]

I have an issue with a sluggish right gimbal on the ST16, despite the pots being sprayed with contact cleaner.
The elevator channel (up/down stick) works exactly as expected - output is instantaneous and returns to zero immediately when the stick is centred.
The aileron (left/right stick) is set up the same but behaves very differently - ouput is zero until the stick is roughly halfway to the maximum input then rises quickly, and when the stick is centred the output only gradually returns to zero.
To complicate matters, up/down stick movements also result in an aileron channel output, despite the fact that the channels aren’t paired.
Video showing the issue is linked below. I have a second ST16 set up the same way which doesn’t suffer the same problem, so it seems like it’s a faulty gimbal or software issue rather than a setup issue. Any pointers or suggestions would be appreciated however.

 

[solder monkey]

Sorry for the sideways video!

 

[WTFDproject]

Create a new model, then see if the problem exists in the new model. I don't think you even have to bind the new model, just create it and see how it behaves.

 

[solder monkey]

Create a new model, then see if the problem exists in the new model. I don't think you even have to bind the new model, just create it and see how it behaves.

Cheers, I just tried that but unfortunately same result. [emoji45]

 

[WTFDproject]

Did you look at the "properties" for each stick to ensure neither channel is listed as mixed with the other? You mentioned that they are not, but this would be a good second check. I'm hoping you have two issues that can be fixed, rather than a controller board issue that will require sending for service.

 

[solder monkey]

Did you look at the "properties" for each stick to ensure neither channel is listed as mixed with the other? You mentioned that they are not, but this would be a good second check. I'm hoping you have two issues that can be fixed, rather than a controller board issue that will require sending for service.

Just checked the properties again to make doubly sure that neither channel was mixed. As expected neither channel is mixed with any other. I’m wondering if the gimbal pot itself is faulty, or if it’s a software glitch.

 

[WTFDproject]

The best guesses would be a bad controller board, some contact between wires on the pot, or something in the software. Have you done any firmware updates or calibrations since the last time the controller was showing normal performance?
The irregular advance, and slow return just sound like problems with the pot. It's the "mixed" behavior that makes it sound like something more.

 

[PatR]

The wiring for both channels connects to a single, multi pin connector at the board. There’s really no chance for them to link from the board connection onwards without a program mix.

I would be inclined to check the Hardware Monitor in the ST-16 to see if the aileron channel was hanging up and not centering at neutral stick. Such does happen, which is indicative of a dirty or failing pot.

If it indicates failed centering try cleaning it again and perform a controls calibration afterwards.

 

[solder monkey]

It’s running the latest firmware. I’m not sure if it’s possible to reinstall the same firmware - I copied the .yuneec firmware file to the root directory of a freshly formatted SD card and tried several times to install it but got a “firmware file not found on SD card dialogue” (I tried it on my other ST16 and with different SD cards and got the same result each time, which is why I think it doesn’t recognise it if it’s the same as the version already installed).
The stick does centre again, but only at the slow rate shown in the video.
I’ll try spraying contact cleaner into the gimbal again and see if that makes a difference.
Failing that it could mean a replacement gimbal, but I haven’t seen these for sale anywhere. In the meantime I have my second ST16 to fall back on.

 

[DoomMeister]

Have you tried removing the gimbal assembly to clean the pots? That allows you to spray directly into the vent on the pot and not saturate other components in the ST-16. You can also check to see if there is a physical reason for the slow return such as the pot is slipping in its mount.

If you suspect a software problem you can swap the left and right sticks (note their orientation in the mounts before doing this). If the problem moves with the stick it is the gimbal assembly. If it stays in the same spot it is software or the controller board.

 

[solder monkey]

Have you tried removing the gimbal assembly to clean the pots? That allows you to spray directly into the vent on the pot and not saturate other components in the ST-16. You can also check to see if there is a physical reason for the slow return such as the pot is slipping in its mount.

If you suspect a software problem you can swap the left and right sticks (note their orientation in the mounts before doing this). If the problem moves with the stick it is the gimbal assembly. If it stays in the same spot it is software or the controller board.

The more I think about it the more I think it must be a software or circuit board issue - if the problem is just with a faulty aileron pot I can’t see how it would also result in an elevator output. There must be something else at play. As suggested, I might try swapping the gimbals over to confirm this.

 

[solder monkey]

Ok, I found this, which looks to be the same problem:

The fix isn’t that clear from the video (I don’t speak polish) but one of the comments suggests using hot glue to fix the problem - I might give it a go.

 

[h-elsner]

From my point of view there are different problems:
a) The value from the gimbal pots follows the stick movents immediately but goes not back to zero. It remains always on the same value differnt from zero if stick was released.
b) The value from the gimbal pots follows the stick movents immediately but goes not back to zero. The value depends on the direction the stick comes from.
c) The values do not follow the stick movement but are slow and delayed.
d) The values do not reach the maximum. Often combined with c).

a) Stick calibration should help.
b) Mechanical problem, pots not fixed as described in #12. Fix it somehow (hot glue, layer or so).
c) and d) Contact problem. I have had c) and d) combined during flight. I have solved it by unplug/plug the connectors from the pots. Additional you should use some gold contact spray (i.e. GOLD 2000).

br HE

 

[solder monkey]

Plan for later today is to open up the ST16, thoroughly clean the pots and connectors, fix the pot connectors with hot glue, and if all this fails swap the gimbals over to try and narrow down the issue.
I’ll let you know how I get on....

 

[solder monkey]

Hi all,
Issue resolved [emoji41]
I gave the pots a thorough cleaning, disconnected cleaned and reconnected the gimbal connectors, and hot-glued the pot PCBs to eliminate any movement or vibration.
Between them this sorted out the issue.
Cheers for all the advice [emoji106]