IMU Calibration Fail, Error 71 & 1, Compass & Gimbal weird - in Iceland

[WhatTheWhat]

SUMMARY:
>1 yr old Mavic pro starts the day fine.
Short flight - rain starts mid-flight, gives obstacle-error (from rain?)
Mavic lands fine, is wet, gets carefully dried off.
Mavic has gimbal error, then compass error, then IMU error.
I update firmware.
Same Error 71. IMU won't calibrate (fails step 1).


DETAILS:
I read a few similar posts, but nothing on MavicPilots matched exactly so...

Been flying my Mavic Pro without problem for over a year. Just got married. We're in Iceland now on honeymoon (wow!) driving the ring road counter clockwise. The situation warrants high spirits, but not having a working drone... To the details:

Took off. Flew 3 minutes, elevation a constant 50 feet, turned around, flew back. While flying back I could feel micro drops of faint rain on my middle-aged bald head. Pushed the right stick to max and headed home flying forwards. Altitude still about 50 feet, no obstacles, no trees for miles here. About 500m from me it stopped suddenly citing "Obstacle Detected", after a slight jog to the right it let me proceed forward. I was able to fly back and land safely. Although the misting was light - Mavic was clearly wet. I *immediately* dried the Mavic with a microfiber towel, paying attention to every surface stippled with little droplets. Mavic back in case, dome covering gimbal.

30 minutes later I go to fly again...
Problem 1: gimbal error (motor too heavy). Tried again with ND filter removed. Same gimbal motor too heavy error. The gimbal can easily rotate in all directions when powering on, but now it gets stuck in the final move - pointing straight down.

I read every post I could find on this, and turns out a wet gimbal can come back to life after it dries out (or so they say). I held in in front of the car's air vent on warm for 5 solid minutes. Now the whole drone is warm (but not hot hot). On boot up the gimbal still fails at the last move, when it points down. Also, now there's an IMU warning - must be calibrated. I held the Mavic in front of the car's warm air vent again while we continued driving east.

Error 71 persists. IMU calibration will start and fail on step 1.
Compass fails to calibrate, even when doing the proper sequence.

I updated the Mavic's firmware. This took a while and seemed to get stuck at 56% for ~5 minutes, but eventually finished successfully. Therefore as of Aug 29, 2018 the firmware is up to date. The Error 71 appeared before I updated, and persists after.

I work in consumer electronics, so I travel with a kit of sorts and opened the Mavic up today (wasn't my first time). Zero traces of moisture or corrosion inside, but I still put it in front of the warm air vent in the car.

After 90 minutes pass:
Gimbal still saying "motor overload" or similar error, despite the gimbal looking physically fine.

Extra info:
I have a Mac with me and a data plan. I don't have DJI Assistant 2 installed, but I could get it.

What should I do next?
Should I chill the mavic in a refrigerator? We have a small one in the van.
I can repair anything, but on this trip it'd have to be purely mechanical (didn't pack a soldering iron).
Any advice much appreciated. This is almost certainly my one and only trip to Iceland.

Thank you for any help.
Rob

 

[Former Member]

gimbal motor too heavy error

Never seen that one before.

Error 71 is usually an accelerometer problem in the IMU. You can try banging the back of the Mavic with your hand to see if the accelerometer gets unstuck, but it usually doesnt work.

 

[WhatTheWhat]

Never seen that one before.

Error 71 is usually an accelerometer problem in the IMU. You can try banging the back of the Mavic with your hand to see if the accelerometer gets unstuck, but it usually doesnt work.

Thanks for the quick reply, Thunderdrones. I tried tapping most of the drone with a spoon today. I'd also opened it up yesterday soon after the crash to check for moisture (none found). I opened it again and took a closer look today, removing and inspecting the obstacle cameras for moisture (none found). I also removed the top back plate to inspect the GPS antenna. That rear board seems fine too. I'm still getting the same errors, and am thus stumped. Any other suggestions? Factory reset?

-Rob

 

[Former Member]

Sorry but I don't think a factory reset is gonna help.

 

[keith00]

Crash? I thought it landed safely. I've seen several posts about Mavics getting very wet without encountering any problems at all. I can't imagine that a few sprinkles would cause these types of problems.

 

[earlyretirement]

I had this same sort of problem a few weeks ago. I've NEVER crashed. Out of nowhere my gimbal was all jello and kept going crazy and wouldn't stay up. I got the calibrate error, etc. The gimbal with DJI has a 6 month warranty and I went to their website and they generated a label to send in to them. You can imagine my surprise when they told me I had to pay $194 to fix it. Just a few dollars in actual parts but then with the various fees it went up to $194. I told them that it's still under warranty. They said I crashed and asked me to upload my flight records which I did and could verify that I NEVER crashed. Not even once. It took 2 weeks of going back and forth and they agreed to subtract $58 (not sure how they came up with that amount). I reluctantly agreed to pay it.

I felt this wasn't fair as it was still under warranty.

On the bright side they sent me a brand new Mavic Pro and no repair. It was totally new.

 

[WhatTheWhat]

Crash? I thought it landed safely. I've seen several posts about Mavics getting very wet without encountering any problems at all. I can't imagine that a few sprinkles would cause these types of problems.

Landed safely and gently, all be it covered in rain drops. From what I can tell the Mavic flew completely normal, even in the light rain, and that the "obstacle" warning was from drop/s of water on the forward obstacle cameras that made it think it was about to hit something. That's a reasonable warning.

This drone has crashed in the past, but not on this trip, and not in many many flights. Still no dice. I have put it in the freezer too. -Rob

 

[WhatTheWhat]

I had this same sort of problem a few weeks ago...

Hi earlyretirement. Thanks for sharing what happened. I'm curious - how long did the repair take? (I assume you have it back). I'm on a 4+ week trip of a life time (expensive) and would pay $195 to get my Mavic working again.

Mine was purchased in June 2017, so... out of warranty.

 

[earlyretirement]

Hi earlyretirement. Thanks for sharing what happened. I'm curious - how long did the repair take? (I assume you have it back). I'm on a 4+ week trip of a life time (expensive) and would pay $195 to get my Mavic working again.

Mine was purchased in June 2017, so... out of warranty.

They sent me a label and it went UPS ground back to them. It went to Grapevine, Texas which is right outside of Dallas near the airport. It took 4 days to get to them once I sent it. The great thing is they have an online status that was totally accurate and up to date. Once they got it, it took only 1 day for them to diagnose and tell me what was wrong and the parts they needed to replace and how much it was. It was funny because some parts only said $1. But the majority of it was for labor.

I fought them for 2 weeks which was painful as they wouldn't answer emails promptly and every time I called them they said I had to wait for the supervisor to review it. I kept pushing and encouraged them to look at my flight records which showed that I never crashed it. And in fact, I asked them if they could see from the logs that it stopped working during a flight when the camera gimbal got all jello-y.

I was still pissed that they didn't pay for the entire thing since it was within the 6 month warranty for the gimbal. (Just barely by a few days). I got tired of fighting with them. They sent me a link to pay via Paypal and the good news is once I did they literally shipped it out 2 days later. It was very quick and I got it back 3 days after they shipped it via UPS.

The unit was totally new not refurbished. So I assume they didn't even bother fixing my old one and I read from others about them getting a brand new drone. It seems like no matter what they weren't going to cover it 100% but I would have spent money shipping back and forth so I thought it was an OK result.

Once they shipped it back, they allowed me to buy the DJI Refresh for $99 which I did. I never crashed it but I figured if I stops working, I'd rather have the Refresh to avoid a long period of fighting with them to repair it.

Good luck!

PS. My error warnings were almost exactly as you described. It wasn't raining at all when mine stopped working but it was VERY hot and humid. I was in Puerto Vallarta, Mexico and it was extremely hot and humid. I think it was something like 100 degrees out with extremely high humidity. I'm not sure if that had something to do with it or not.

 

[WhatTheWhat]

...They said I crashed and asked me to upload my flight records...

2nd reply - how do you export the flight logs from a Mavic? I've got a Mac and searching for an app that pulls the logs (and actually works) is coming up empty.

-Rob

 

[earlyretirement]

2nd reply - how do you export the flight logs from a Mavic? I've got a Mac and searching for an app that pulls the logs (and actually works) is coming up empty.

-Rob

They just had me go to my DJI Go 4 App and go to my flight records section and just synch it so all my flight records would update to their server. I'm not sure what all they can see but every single one of my flights is recorded there and I can see a simulation of each flight. How far I went, how high, GPS coordinates, etc.

Just go into your App and go to the "Me" section and Go to Flight Records.

 

[WhatTheWhat]

They sent me a label and it went UPS ground back to them. It went to Grapevine, Texas which is right outside of Dallas near the airport. It took 4 days to get to them once I sent it. The great thing is they have an online status that was totally accurate and up to date. Once they got it, it took only 1 day for them to diagnose and tell me what was wrong and the parts they needed to replace and how much it was. It was funny because some parts only said $1. But the majority of it was for labor.

Hi Earlyretirement, and sorry for delayed response. We finished the Iceland part of our trip and are now in Amsterdam. As luck would have it our AirBnB is owned by an action-sports videographer. He took a look at my Mavic and said he'd never seen an IMU error that constantly fails calibration - so today I will ship it to DJI for repair and hope it's not too expensive. Here I must ship it to their repair facility in Rotterdam, Netherlands. It's only an hour drive from Amsterdam (great for low shipping cost) but since we leave tomorrow it'll have to be shipped to one of our next destinations (a cousin in Switzerland) when done. That should be interesting to track! Thank you for mentioning that the DJI repair status and shipping was easy to follow.

Off to the post office. Will update the thread when I get the bill.
Cheers.

 

[WhatTheWhat]

DJI DIAGNOSIS:

Item Quantity Unit Price（EUR)
Compass Board 1 2.48
Middle Frame Module 1 4.13
Core Board 1 273.55 <----- whoa
Upper Cover 1 0.83
Rear Left Motor Arm 1 18.18
Repair Service Fee 1 50.00
Freight： 25.00
Discount： -0.00
DJI Care deduction： 0.00
Sub Total Payment： 374.17
VAT(at 21%)： 0.00
Grand Total Payment： 374.17 EUR = $449.69 = OUCH.

The Mavic had indeed crashed on August 18th, but flown 6 times flawlessly since then... then mysteriously the Error 71 on the Southern coast of Iceland. Related..?.. now on my iPhone when I'm following Google Maps walking directions my phone always thinks it's off by 90 degrees, as if the compass has been permanently skewed and rebooting has no effect.

Anyone else getting compass errors in extreme latitudes, or in Iceland?