Today I started noticing a vibration problem somewhere.  My footage has started to get the "jello" effect, I've calibrated my gimbal, IMU, compass.  I suspect it's not the gimbal. The vibration/imbalance was so bad earlier in the day that after launch I couldn't control it and it crashed.  Don't know what started it, wasn't a problem yesterday.  After replacing many props (OME) it's flying much better but I'm still getting the jello.  Problem is I can't see any damage or imbalance or malfunction that might be causing vibration.  One thing I'm noticing is on a smooth flat surface once the props start spinning the whole aircraft starts to slowly rotate on the floor clockwise.  I don't recall it doing that before and I wouldn't think it should, does that happen for other people?  Might that suggest something?  Thanks for your thoughts!

It's possible this is a silly question, but are the props oriented correctly?

Hi, PsyDious. Thanks for reaching out, and we're sorry for the inconvenience. We want to help you check it further. Kindly post a short video showing the jello/rippling effect and another video of its behavior when placed on the ground. We will be waiting for your update. Thanks for your cooperation.

You say you replaced props, each time you replaced a blade did you replace BOTH blades on the motor using the two blades from the replacement pack?
DJI you use DJI props or some after market pattern props?

Does sound like one of the props has the reverse pitch on it, but it started spontaneously, you say. Check if any of the motors has resistance, if you twiddle them around. Maybe one motor is seizing up.

Zhillz Posted at 4-2 20:41
It's possible this is a silly question, but are the props oriented correctly?

Yeah that's not the issue, but thanks!

Zoooom Posted at 4-2 23:25
Does sound like one of the props has the reverse pitch on it, but it started spontaneously, you say. Check if any of the motors has resistance, if you twiddle them around. Maybe one motor is seizing up.

None of the motors feels or looks off to me

Tends to mean the motor control board is sending the wrong speed to one of the motors. Could be recorded in the dat/log file, but no doubt you will have to send it back to DJI.

Here are two videos, one shows the jello effect and one shows the rotating drone on the floor.  As you can see I think the props are correctly placed.  On closer inspection I think the problem is with the left front motor, that arm keeps appearing to me to be vibrating more than the rest, though it doesn't feel or look damaged to me, the motor seems to spin just fine.  Maybe Zooom's "wrong speed" theory is correct?

https://youtu.be/DSyGX1cYt5w

https://youtu.be/zxT5qdGK-jI

Does it always rotate clockwise, can you post the DAT log for an on the floor rotation?

Sean-bumble-bee Posted at 4-3 10:51
Does it always rotate clockwise, can you post the DAT log for an on the floor rotation?

Always clockwise.  I can't post a log because I've decided to just ship it to DJI, it seems unlikely that the cause of the problem is something I can fix on my own, whether it's a problem with a motor, an arm, or the control board.  If I learn more from DJI I'll try to post it here.  But thanks for offering to look at it!

PsyDious Posted at 4-3 11:24
Always clockwise.  I can't post a log because I've decided to just ship it to DJI, it seems unlikely that the cause of the problem is something I can fix on my own, whether it's a problem with a motor, an arm, or the control board.  If I learn more from DJI I'll try to post it here.  But thanks for offering to look at it!

If your concern regarding the DAT is a 'confidence' or risking antagonising them then fair enough. that you entirely your choice.
However if you think you no longer have the DAT then the DAT needed is on your screen device.... unless you have synced logs, in which case it may have been deleted during the sync.

Of course, either way it remains your choice.

Sean-bumble-bee Posted at 4-3 12:05
If your concern regarding the DAT is a 'confidence' or risking antagonising them then fair enough. that you entirely your choice.
However if you think you no longer have the DAT then the DAT needed is on your screen device.... unless you have synced logs, in which case it may have been deleted during the sync.

Ah I didn't realize you could download the logs without the drone.  Ok I've uploaded one here if it's of any use:

https://www.phantomhelp.com/logviewer/38Q18U7X6CS16KROS9GG

PsyDious Posted at 4-3 13:02
Ah I didn't realize you could download the logs without the drone.  Ok I've uploaded one here if it's of any use:

https://www.phantomhelp.com/logviewer/38Q18U7X6CS16KROS9GG

Thanks but that is the .txt flight log, the one I was after is the DAT flight log. It contains motor speeds. If it exists it should be in the MCDatFlightRecords folder which is in the folder where you found the .txt flight log, its name will probably contain "FLY162".
If you have synced your logs with DJI the DAT may have been deleted.

Sean-bumble-bee Posted at 4-3 13:27
Thanks but that is the .txt flight log, the one I was after is the DAT flight log. It contains motor speeds. If it exists it should be in the MCDatFlightRecords folder which is in the folder where you found the .txt flight log, its name will probably contain "FLY162".
If you have synced your logs with DJI the DAT may have been deleted.

Oh got it, ok I don't know how to upload that here so I just put it in Dropbox and here's a link:

https://www.dropbox.com/s/zjf4hlj5hir1o4t/2023-04-03_12-53-01_FLY163.DAT?dl=0

Thanks but that is the DAT for the next drone power up, FLY163,The one wanted is  "FLY162".
FLY163 does not contain useful DAT.

Sean-bumble-bee Posted at 4-3 17:17
Thanks but that is the DAT for the next drone power up, FLY163,The one wanted is  "FLY162".
FLY163 does not contain useful DAT.

I'll get it right one of these days...

https://www.dropbox.com/s/6jk1umlnlxcvpkw/2023-04-03_12-44-14_FLY162.DAT?dl=0

Oooh that's better but drat, I had wondered if it would show a diagonal pairing of the motor speeds, that's that idea torpedoed.

BTW multply the motor speeds by 10, I think.

Sean-bumble-bee Posted at 4-3 18:58
Oooh that's better but drat, I had wondered if it would show a diagonal pairing of the motor speeds, that's that idea torpedoed.

BTW multply the motor speeds by 10, I think.

Well I appreciate the look-see anyway, it's always fun to look at diagnostics!  

PsyDious Posted at 4-3 09:08
Here are two videos, one shows the jello effect and one shows the rotating drone on the floor.  As you can see I think the props are correctly placed.  On closer inspection I think the problem is with the left front motor, that arm keeps appearing to me to be vibrating more than the rest, though it doesn't feel or look damaged to me, the motor seems to spin just fine.  Maybe Zooom's "wrong speed" theory is correct?

https://youtu.be/DSyGX1cYt5w https://youtu.be/DSyGX1cYt5w

Thanks for posting the videos. We'll have them forwarded for feedback. We just need to confirm some more details. Is the "jello effect" occurring in the original video as well? And did the drone started turning clockwise when the motors starts right after it crashed? Are you getting any specific error messages on the app? Thank you.  

DJI Tony Posted at 4-4 23:57
Thanks for posting the videos. We'll have them forwarded for feedback. We just need to confirm some more details. Is the "jello effect" occurring in the original video as well? And did the drone started turning clockwise when the motors starts right after it crashed? Are you getting any specific error messages on the app? Thank you.

The jello effect started the day before the particular crash I referred to.  I don't know when exactly it started turning clockwise, on a non-smooth surface there was enough friction to hold it in place.  And no I was not getting any error messages.  After the crash I referred to I started getting gimbal errors but recalibrating fixed that.  Hope that helps.  

Calibrate the IMU.

djiuser_p8CiIxkux2Tl Posted at 4-5 08:18
Calibrate the IMU.

Thanks, already tried that.

PsyDious Posted at 4-5 08:42
Thanks, already tried that.

Stick calibration ?  if the sticks in mid postion gives input...

can you share a flightlog for this issue?

cheers
JJB

JJB* Posted at 4-5 09:49
Stick calibration ?  if the sticks in mid postion gives input...can you share a flightlog for this issue?

https://www.phantomhelp.com/logviewer/38Q18U7X6CS16KROS9GG
Try copying the link in post #13 and pasting it into your browser's URL window. As a link that link, in post #13, is broken but a copy and paste etc. works.

Sean-bumble-bee Posted at 4-5 10:15
https://www.phantomhelp.com/logviewer/38Q18U7X6CS16KROS9GG
Try copying the link in post #13 and pasting it into your browser's URL window. As a link that link, in post #13, is broken but a copy and paste etc. works.

No 'false' stick input when craft is yawing.

In the 8 blades are installed correctly, IMU has been calibrated....not much more what can be done.

cheers
JJB

PsyDious Posted at 4-5 04:05
The jello effect started the day before the particular crash I referred to.  I don't know when exactly it started turning clockwise, on a non-smooth surface there was enough friction to hold it in place.  And no I was not getting any error messages.  After the crash I referred to I started getting gimbal errors but recalibrating fixed that.  Hope that helps.

Apologies for the delayed update. Kindly perform the following troubleshooting steps:
For the "jello effect":
1. It is recommended to either increase the exposure time by using an ND filter or shrinking the lens aperture, or reducing the flight attitude angle to get a better picture effect.
2. Check whether the gimbal is released from the limit buckle. If not, calibrate the gimbal and IMU in the DJI Fly app, and then check whether the issue still exists.
For the drone rotating clockwise when placed on a flat surface:
1. Check if the propellers are installed properly. You may also try replacing the propellers to see if it helps.
Please keep us updated. Thank you.

DJI Tony Posted at 4-9 23:31
Apologies for the delayed update. Kindly perform the following troubleshooting steps:
For the "jello effect":
1. It is recommended to either increase the exposure time by using an ND filter or shrinking the lens aperture, or reducing the flight attitude angle to get a better picture effect.

Thanks, none of those are factors for this problem.  DJI has the drone now, I'll share if I learn more.  

PsyDious Posted at 4-10 07:02
Thanks, none of those are factors for this problem.  DJI has the drone now, I'll share if I learn more.

Thanks for your understanding and for considering sending the drone in. We hope the process goes smoothly for you. Have a nice day.

So if anyone is still following this thread, DJI has diagnosed the problem as an issue with the left front rotating arm axis (consistent with my observation of vibration).  They sent me the following pictures, I can't actually tell what's wrong from the pic but at least it's repairable!  The pic of the diagnostics is apparently supposed to show nothing wrong there.  

From memory the actual front arm pivot is clamped to the middle shell of the the drone's body, by three screws. The rear arms of the Mini 1 & 2  have a similar arrangement. If those screws have come loose then the pivot itself and thus the arm, could wobble.
Alternatively the actual pivot could be failing and have play in it.
A third option might be that the am's pivot bore has stretched and is no longer a tight fit around the actual pivot.
Fourth option, the ringed screw and its mate (if there is one) have come loose and are allowing the arm to move relative to the actual pivot. I think the first two options are more likely than the latter two but that's guess work.

With regards to the photo of the app, I can't help but wonder where the other end of the cable is? But I suppose it could be masked by the antennae etc. lol.
Are they treating it as a warranty issue?

Sean-bumble-bee Posted at 4-11 06:18
From memory the actual front arm pivot is clamped to the middle shell of the the drone's body, by three screws. The rear arms of the Mini 1 & 2  have a similar arrangement. If those screws have come loose then the pivot itself and thus the arm, could wobble.
Alternatively the actual pivot could be failing and have play in it.
A third option might be that the am's pivot bore has stretched and is no longer a tight fit around the actual pivot.

Yes indeed they are treating it as warranty, and kudos to DJI for the quick assessment and pictures!

.. brilliant ..

#Quick Reply Here#The fact that the aircraft is rotating on a smooth surface when the props start spinning is a cause for concern, and could be an indication of an imbalance in the drone's motors or propellers. It's important to check that all of the propellers are securely attached and not damaged or bent, and that the motors are functioning properly.  If you've already replaced the props and the vibration is still present, it may be worth contacting the manufacturer or a professional drone repair service for further assistance. They may be able to perform a more thorough inspection and diagnose the issue.