Infamous stuck motor issue strikes again

[c64-dev]

Hey all,

I am in a bit of a bind here and I would very much appreciate your help.

Just recently I had to take the painful decision to part with expensive bits of kit that see little to no use due to time constraints; unfortunately the Mini 2 is one of them.

Now, I've had the drone a little under a year and in that time it has literally flown 4 times including today. The drone is immaculate, always kept in its bag or on a dust free shelf, never crashed, made sure to hand launch when I was in an environment where dust could be an issue etc etc.

So today I meet a person interestedin buying the Mini and we do a test flight. I put the drone on the pavement, manually start the motors and I notice that the left front props are not spinning and shortly after the others stopped (or could be that I stopped them, can't remember).
I pick up the drone and try to spin the props and I notice that they seemed to be stuck. The props would turn but veeeery reluctantly and the whole rotor seemed to be "dragging" for lack of a better word. The other 3 motors spin very easily and would go from magnet to magnet very crisply/distinctly.
The stuck one felt like it was gummed up.

I looked at the motor and didn't see anything out of the ordinary. After a while, rotating the props the motor seemed to free up and eventually it felt fine. I started the drone, let it hover and then flew a whole battery around with absolutely no issue at all.
However, upon landing the left front motor seemed to be gummed up again.

Obviously i had to put the sale on hold until I address the issue.

I purchased the drone directly from DJI online 345 days ago. I guess I should send the drone back to DJI but I feel reluctant to do so for the following reasons:

1. I am afraid they will replace my new drone with a refurbished one, which I would not want under any circumstances.
2. Would the drone need to be shipped off to China? If so It would be a huge hassle to do so, let alone the costs associated with posting.
3. I think that you now need to send the drone plus the controller back, which would make posting ever more of an issue.
4. I heard that when DJI gets a drone back for repair they update to the latest FW, which I want to avoid as I am on 1.3 and want to stay there.

Also, would I be covered under warranty? How likely would it be to tell me that they will be charging me for the repair?

To cut a long story short; I would prefer to fix ONLY the motor under warranty and locally ideally. Would this be possible or am I looking at opening up a repair case with DJI etc etc?

 

[vindibona1]

I purchased the drone directly from DJI online 345 days ago. I guess I should send the drone back to DJI but I feel reluctant to do so for the following reasons:

1. I am afraid they will replace my new drone with a refurbished one, which I would not want under any circumstances.


Also, would I be covered under warranty? How likely would it be to tell me that they will be charging me for the repair?

To cut a long story short; I would prefer to fix ONLY the motor under warranty and locally ideally. Would this be possible or am I looking at opening up a repair case with DJI etc etc?

1) DO NOT BE AFRAID OF A REFURBISHED UNIT. DJI's refurbs are indistinguishable as "new" units. I bought a refurb M2P over a year ago. When it came I wash shocked that it was brand new in every aspect, down to the packaging.

2) I'm not sure about the warranty and how DJI would respond to a warranty claim. There are some private repair services out there, who would probably repair it relatively cheaply. But failure to repair it makes it a paper weight and unsaleable..

 

[c64-dev]

Just now I decided to power up the drone and see what it would do with the motor that felt stuck.

I started the motors manually and surely enough only 3 started spinning with the front left one refusing to budge. On DJI Fly I got the following message:


However, when I tried starting the motors again right after that message all props started immediately and no errors came up.
Tried 3 more times and started up fine every single time.

 

[Yorkshire_Pud]

Since it is still presumably under warranty DJI are, as far as I know, responsible for the carriage cost and even if there are not legally bound to do so I believe they 'cover it' in both directions.
Secondly I think it is more likely that your drone will go to a European repair centre than a Chinese one and probably Amsterdam.
By all accounts a DJI refurbished drone is as good as new. Given that the Mini 2 is still being sold I woud say you have a fair chance it actually will be a NEW drone.
Given that you probably have 20 days warranty left do not delay in starting the process.

 

[c64-dev]

So the consensus is that I would be getting a replacement drone right?

With that in mind, do you guys know if they would be updating the FW to 1.4? I don't want that under any circumstances as there is no rollback and DH no longer works with that one...

By the way, the more I look at the issue I'm shocked just how common it is... I found several threads about it on DJI forums, here and Reddit...

 

[c64-dev]

Speaking of replacements...
Ever since I got the drone (And again, bought it brand new from DJI) it had some scuffs on the gimbal, which I found to be weird for a brand new product. It never affected the image quality in any way, so I promptly forgot about it, but speaking of refurbished products I remembered it.
When you buy a brand new drone, is it possible to be getting a refurb unit instead?


Now that I've been playing with the props to see if I can fix the stuck motor, I noticed that 2 of the other bell housings have some light specs on them, almost like pitting. I assume that these are aluminium, so could this be some slight corrosion?

 

[Yorkshire_Pud]

Bear in mind that forums etc. see a skewed sampling, FAR MORE people post problems than "sing praises" in fact people rarely post to sing praise.

With that in mind, do you guys know if they would be updating the FW to 1.4?

You will get what you get, I doubt you have control of what you will recieve.
Besides, I wouldn't be surprised to find an authorised repairer would be obliged to update the firmware, they are not allowed to sell parts apart from props and batteries etc. If "obliged to update firmware" is correct and you are adamant that you do not want the firmware then your only choice is to fix it yourself, i.e. replace the motor and most likely the arm and motor.

Just curious, if you are selling why are you bothered about what firmware is on it?

 

[c64-dev]

@Yorkshire_Pud thanks so much for taking the time to give insights. Much appreciated!

About the firmware, believe it or not, a lot of people who have called up about the drone are asking if the FW is downgradeable or not; they've heard about the issues surrounding 1.4 and they want to steer clear.

 

[Yorkshire_Pud]

@Yorkshire_Pud thanks so much for taking the time to give insights. Much appreciated!

About the firmware, believe it or not, a lot of people who have called up about the drone are asking if the FW is downgradeable or not; they've heard about the issues surrounding 1.4 and they want to steer clear.

I know, I don't up date either but if you want it repaired by DJI or their agents I suspect you have no other option and I think the not-being-able-to-roll-the-firmware-back thing STINKS. I got caught out by that with one drones and have removed my drone 'phones' from my wifi to prevent any chance of notifications being recieved (they have no sim cards).

 

[c64-dev]

The more I look at the situation, the more I realize i basically have two options here:
A. Send the drone in and accept whatever replacement/repair comes along with the downside of having the dreaded 1.4 firmware
B. Keep it as is and either try to find a fix for the motor or find a replacement motor.

The biggest problem I have with option A is that seeing as this stuck motors problem is quite widespread, there is no guarantee that I wouldn’t end up with a 1.4 FW on the replacement drone AND a stuck motor shortly afterwards. Yes, I am considering selling the drone but the last thing I want is an angry buyer calling me a month later and telling me that I hid the issue from him/her.

I really don’t know what to do here... This absolutely sucks; the wee little mini is brand new and immaculate. Such serious issues shouldn’t be happening so soon.
Case I’m point: a couple years back I got an old Phantom 3 standard with very bad range issues which I fixed and proceeded to flying in all kinds of conditions. The motors never ever missed a beat.

 

[c64-dev]

@Chaosrider IIRC you have 4 minis. Have you ever experienced any issues with stuck motors on yours? Could it possibly be that I am so unlucky?

 

[c64-dev]

Update: it increasingly looks like I may not have any warranty on the Mini.
I checked on DJI service center and I tried to request a set idea online and for my serial number it says: Service Plan Status Unavailable

Also, DJI on their website mentions that the limited warranty (which I assume is 1 year) starts counting from the date of purchase. If that’s the case, with the drone activated 345 days ago, when I actually received the drone, it is safe to presume that the warranty has expired by now.

On top of that, Cloud city Drones has an excellent analysis of DJI’s warranty T&Cs and it claims that for propulsion specifically the warranty on most DJI drones is actually 6 months. this info might be outdated.

The engineer in me is glancing sideways at the stuck motor while we speak...

 

[Yorkshire_Pud]

I would check the law.
It maybe be UK only (and not applicable to Finland) but I have the impression that under distance selling regultaions here in the UK warranty starts from the arrival/receipt of the goods.

If I am wrong someone please correct me.

 

[c64-dev]

I'll definitely check it out. I think consumer laws are the same in all the EU countries and UK.

However, there's no escaping the fact that DJI online repair system is saying Service status unavailable.

Anyway, continuing on my morning rant about this issue, I am pretty certain I've identified the culprit: taking apart the props to have a better look, it seems like there are some burn marks on the shaft well of the motor. The mark appears to be some oily substance, as it comes off with a toothpick.

This is how the problematic motor looks like...


....vs the other motors. Notice that none of the others have this yellowish/Brown tint on the centre shaft.

 

[Yorkshire_Pud]

Either on here or the DJI Forum there is a thread with photo/s of a dismantled Mavic Mini or Mini 2 motor. You might like to look for that thread and compare its photo/s with yours.
It might not be a bad idea to post your own story on the DJI Forum too. It might get a mod's attention.

 

[c64-dev]

Either on here or the DJI Forum there is a thread with photo/s of a dismantled Mavic Mini or Mini 2 motor. You might like to look for that thread and compare its photo/s with yours.
It might not be a bad idea to post your own story on the DJI Forum too. It might get a mod's attention.

I couldn't find this thread, but I did find a video on dismantling a bigger DJI motor. The guy had to use a press to push out the shaft; I am not going to such lengths for the wee little MM2 motor.

Ideally I would like to get a new motor. Replacing the whole assembly is quite straightforward. Shame I need to deal with such issues on a brand new drone though.

 

[Yorkshire_Pud]

Found it

Bearings motor

Guys, one of my motors has clearance in the bearing, does anyone know the measurement of the bearings, I'm looking to change it and I don't need to buy a new motor or arm for the mini2, it flies normal, but the clearance is already leaving the motor with a minimum of vibration.

forum.dji.com

You'd do better to look for an arm and motor, if you get a motor only you'd have to separate the motor's wires from the antenna's wires and more awkwardly re feed all the wires through the arm and any sheathing around them. Plus you might damage the antenna or its solder joints in the process.

 

[Chaosrider]

1. I am afraid they will replace my new drone with a refurbished one, which I would not want under any circumstances.

Why not? I've gotten a couple of re-furbs back from DJI, and they have been in perfect condition. Like new, as far as I could tell.

If DJI fixes it under warranty, they'll probably pay shipping both ways.

Good luck!

MM

 

[Chaosrider]

Just now I decided to power up the drone and see what it would do with the motor that felt stuck.

I started the motors manually and surely enough only 3 started spinning with the front left one refusing to budge. On DJI Fly I got the following message:
View attachment 146826

However, when I tried starting the motors again right after that message all props started immediately and no errors came up.
Tried 3 more times and started up fine every single time.

I think the drone was just annoyed with you because you had flown it so little...

;-)

More seriously, if a drone sits for a while, it sometimes needs a couple of "limber up" flights.

I took two years of auto shop in high school, and then I owned/operated a number of aircraft. One important piece of wisdom that I picked up somewhere is:

"The best preventive maintenance is regular use."

I had a drone returned to me after it had been missing out in the elements for 10 months. I cleaned it up carefully, but when I went to fly it, the two front props started, and the rear props didn't. I hadn't expected that, but I decided to goose it with just a bit more power, and Presto! The drone was flying.

Good luck!

MM

 

[Chaosrider]

So the consensus is that I would be getting a replacement drone right?

With that in mind, do you guys know if they would be updating the FW to 1.4? I don't want that under any circumstances as there is no rollback and DH no longer works with that one...

By the way, the more I look at the issue I'm shocked just how common it is... I found several threads about it on DJI forums, here and Reddit...

Yes, that was my experience with DJI repair. I got a replacement back after sending them in for repair. I actually didn't expect that, but it worked out fine.

I always stay current on the FW, so I wouldn't know about that.

I haven't quite finished the thread, but is there any reason to believe the drone isn't working fine now?

Thx,

MM