Took a month to arrive. Loaded up the software, waited for the updates, ready to go. Lift-off! Fail - one of the three motors does not turn freely. No debris that I can see, and it is straight out of the box.

Anything to try before I send this thing back? If I do, I hope I can get my $49 "Care" order refunded also.

The debris will be very tiny in most cases, probably particles from the motor's magnet. Warranty issue.

Hi chkaloon, I am sorry to hear about the case. Could you please provide a video of the motors' issue? You can twirl the motors so we can check the differences. Please also provide the serial number of the drone.
If there is no debris, and it's the motor's issue, you may contact the retail store to see if they can help you directly. If they would not help, you can send the drone to our service center for further assistance.
If the drone was returned, you can send the return receipt to djicare@dji.com for the refund request of DJI Care Refresh.

It was DOA, and I bought it off Amazon, so I will probably just return it. I'm not going to send it to a repair center and wait another couple months to get it back.

I'm frankly surprised how exposed those motors are. They must get returned or repaired all the time for this issue.

As GaryDoug pointed out in Post #2 the debris will most probably be so tiny that it can't be seen by the naked eye.  I've had a motor issue and tried to blow debris out, etc but to no avail.  The shavings were so tiny and still magnetized and simply would not come out.  It's not a really hard DIY issue but DJI does not recommend DIY as it voids your warranty.  As your drone is new and it happened right out of the box I'd say return it immediately.  Otherwise you could be looking at a lengthy timeframe to ship to DJI and back as a warranty issue.  

Since the motors are exposed (to help cool them while flying) I always hand take off/land to preclude any debris getting into the motors.  

same happen to me they replaced

I had the exact same experience with the mini right front motor stiff right out of the box. Seems like a really common problem.

You could try removing the props and then vacuuming the motor or work a sliver of paper between the poles of the stator and the bore of the rotor,  once successfully inserted attempt to saw the paper around the outer of the stator. You'd probably need to do this in each opening in the top of the motor but one opening at a time.
No guarantee of success though.
Other than that return it to Amazon.

I experienced a similar issue. I inspected the unit on unboxing and found the front left rotor didn't turn by hand freely (pushing the blades made the drone slide around on the wood floor rather than turn the motor), and a dent in the front left arm where the antenna is. I flagged both items with DJI and was told I could return it to where i bought it, or send it in for repair. Sadly I got into a really frustrating "you can't return that to our store because you opened the box" with our local electronics store here...(that part was not DJI's fault).

Finally, after dozens of frustrating phone calls with our local store, and almost deciding I was going to send this device to DJI for a teardown and new arm, I tried using one of those bulb-squeeze air puffers designed for SLR camera dust cleaning and pushed some medium-pressure air through the top of the motor housing. I was really surprised but this immediately fixed the issue. I'm writing this here for anyone else's help in the future.

chkaloon Posted at 2021-1-9 21:15
I'm frankly surprised how exposed those motors are. They must get returned or repaired all the time for this issue.

how the situation ended?

fateofangel Posted at 7-18 13:33
how the situation ended?

I had a minor bump on my mini2, after which one motor would not turn properly.  It turned out that one of the tiny magnets in the rotor was no longer glued to it's proper spot.  This was very hard to notice as it was quite close, and didn't move around given the strong magnetism.   I was able to remove it, and the drone works as if nothing is wrong.

fansb4f50ec1 Posted at 7-19 11:36
I had a minor bump on my mini2, after which one motor would not turn properly.  It turned out that one of the tiny magnets in the rotor was no longer glued to it's proper spot.  This was very hard to notice as it was quite close, and didn't move around given the strong magnetism.   I was able to remove it, and the drone works as if nothing is wrong.

Great to hear than

fansb4f50ec1 Posted at 7-19 11:36
I had a minor bump on my mini2, after which one motor would not turn properly.  It turned out that one of the tiny magnets in the rotor was no longer glued to it's proper spot.  This was very hard to notice as it was quite close, and didn't move around given the strong magnetism.   I was able to remove it, and the drone works as if nothing is wrong.

Did you apply the tiniest smear of glue etc. and reinsert the magnet, if not then the motor is out of balance.

The motor diameter is around 18mm so lets say the magnets CoG is 8mm from the axis of rotation, Mavic Mini  motors run north of 10,700rpm, I am on the wrong computer to process any DATs. 10,700rpm is from a random csv of one of the DAT's that I have previously processed. I think I have seen RPM in excess of 12,000.
I suspect a mini 2 will not be far behind. Plug 10,700rpm @8mm into the calculator
https://www.calctool.org/rotatio ... n/centrifugal-force
and you get.......well look for your self, switch the "centrifugal acceleration (a)" to g to see how many g (earth gravity) the magnets are feeling.

I would hover the drone and touch the underside of the motor mount/arm and check how much vibration you feel.

Sean-bumble-bee Posted at 7-19 15:36
Did you apply the tiniest smear of glue etc. and reinsert the magnet, if not then the motor is out of balance.

The motor diameter is around 18mm so lets say the magnets CoG is 8mm from the axis of rotation, Mavic Mini  motors run north of 10,700rpm, I am on the wrong computer to process any DATs. 10,700rpm is from a random csv of one of the DAT's that I have previously processed. I think I have seen RPM in excess of 12,000.

I wasn't able to position it in place, let alone hold it there long enough to have glue set.

I have tried to feel or see or hear a difference but can't.  I even have a Flir and wasn't able to detect a temp difference with that.  I plan to replace the motor, but it's not a rush for me as that drone doesn't get much use now that I have a mini 3.

I read a post recently where someone spoke about a data file and observations about individual motor speeds.  Any idea what tool would let me extract motor speeds?

Unfortunately I believe the relevant logs from the Mini 2 are unreadable by us mere mortals, they are encrypted, only DJI can read them. This is why I cited Mavic Mini data.
Those logs are referred to as ''DAT's'', due to their extension being .DAT .
DJI drones generally record two DAT's, one to the drone and the other to the screen device. The DAT's on the screen device are likely deleted if you sync your logs with DJI. The DAT's on the drone are short lived due to limited storage space the old logs are over written.

To read readable flight logs, both .DAT & .txt, I use CsvView.      DatCon is an alternative for DAT's and I use the relevant version of TXTlogToCSVtool in a command line one liner to process .txt's en-masse.
For CsvView & DatCon see https://datfile.net/CsvView/downloads.html
For TXTlogToSCVtool see https://phantompilots.com/thread ... sv-converter.70428/
Unfortunately neither CsvView nor TXTlogToSCVtoolMM can process the .txt from the Mini 2 so you have to upload the logs to https://www.phantomhelp.com/logviewer/upload/ and then down load the csv. That csv can be opened in a modern spreadsheet program and are useful in their own right but you can also open these csv's with CsvView and produced graphocal charts.
There is also Airdata, which gives access some data that Phantomhelp does not but the Airdata csv contains a very limited amount of information and I prefer the Phantomhelp csv.


JJB, a member here, has some software, ''FRAP'', https://forum.dji.com/thread-203659-1-1.html    but I have never got round to using that, from memory that works off the Phantomhelp csv.

You might also find this interesting https://mavicpilots.com/threads/ ... alysis-guide.78627/

Hello

I´d just unboxed a brand new with one stuck motor, and I managed to fix it by hand rotating it gently back and forth for a few minutes. Drone went straigth up flying afterwards :-) ..

Cheers

Skipper_dk Posted at 10-13 11:59
Hello

I´d just unboxed a brand new with one stuck motor, and I managed to fix it by hand rotating it gently back and forth for a few minutes. Drone went straigth up flying afterwards :-) ..

Hi Skipper_dk. This will definitely help users who will have the same issue with their new drone.  Yes, you can manually rotate the motor to fix this issue while the drone is powered off. The propulsion motor of the Mini Series is designed with a spherical bearing. During transportation and storage, the bearing may move within the motor, which leads to the issue. As the spherical bearing cone can be manually adjusted, you can manually rotate the motor to fix this issue.