Troubleshooting

[smrtalex]

This is for a Mavic Pro that I recently was gifted.

It functioned perfectly prior to it's crash and being submerged in fresh water. It has been allowed to dry and put in a bag of rice for a substantial period of time. There was no external damage to the RC.

The AC and RC turn on, but I cannot get then to connect. Trying to get a fresh start and just using the RC for right now to make the connection, no wifi (I will get back to that).

Both AC and RC are fully charged (using a different battery than the one that went in the water). With the RC switch on 'rc', I turned on the AC and RC. The RC says 'connecting'. Then goes away and leaves me with the RC icon in the upper right that appears to be searching for signal and battery power left. Other than that the screen is blank. On the AC, after turning it on, I get the 2 red lights on the front arms on, no rear light comes on at all during the startup process, and the light by the rc/wifi switch is green. Also, the camera will move a little bit, like it is calibrating. Over time, I can hear the fan on both the AC and RC come on. But I never get a connection.

I also tried to relink (binding). With the RC in 'binding', I push the button near the rc/wifi switch and it turns from green to red. It does not appear to bind or make the connection.

I turned everything off, and did a firmware update on both the AC and RC via DJI Assistant 2. Both units were successful with the firmware update! Which I consider great news. Also during the update on AC, all of the lights seems to be working, including the rear light which did change colors a few times.

Once that was complete, I retried the connecting and received the same behavior as listed above. No connection.

I tried the rebinding again. On the AC, I push the button near the rc/wifi switch and it turns from green to red. When I put the RC, in binding, the light changes from red back to green. So it acts like it is doing something, but does not appear to bind or make the connection.

I then powered the units down, moved the switch from 'rc' to 'wifi' and turned on the AC. I then checked my phone to see if the network was broadcasting. It was not. So I concluding that the wifi board, had likely failed. I ordered one up. Took apart the drone. Carefully replaced the wifi board.

I then retried the connecting. Same thing. No connection. Now it appears that the fan on the AC is not coming on, although I am not 100% sure on that. Apparently the wifi board was not the issue.

Does anyone have any suggestions on what further I can to to troubleshoot the unit and isolate what, if anything, needs to be replaced?

Thanks in advance!

 

[old man mavic]

this may sound strange but have you got a SD card in the drone a new one i mean give it a try

 

[smrtalex]

Thanks! I will try anything at this point!

There was no card in previously, so I did try the SD card (new and blank) and received the same behavior. No connections!

So I tried to relink (binding). With both AC and RC on, I pushed the button near the rc/wifi switch and it turns from green to red. Put the RC in binding mode. The RC displays binding very briefly, the goes blank with just the battery usage and the RC remote icon in the upper right just looks like it is searching for a signal. But the AC light turns from red back to green, which I would think tells me there is some type of connection attempting.

Also, just tried this. Both AC and RC on. But RC in Binding (showed binding on the screen and beeping). Went to the RC and pressed the button near the switch (light was green). Light turned red then green and the beeping and binding went away on the RC.

Any other thoughts?

 

[old man mavic]

it would seem that the water has shorted something inside the drone, does the fan come on after a while, and does the gimbal do its startup dance

 

[smrtalex]

I am thinking the same thing, but not sure what on shorted. I do know that the fan did come on before I did the wifi board swap. Everything was meticulously reconnected so I know I did not miss any connections. Typically, how long is the drone on before the fan kicks on?

The gimbal does do its startup dance. I am suspecting the lower board is fine as I was able to successfully update the firmware on it. But I could be wrong.

I just don't know all the parts and how they interact with each other to know what might need to be swapped out or how to test/troubleshoot to determine what is wrong.

 

[old man mavic]

when you have your screen device attached to the controller and you have the go4 start screen on the app showing then you turn on the controller after a short time it should connect to your device and will say controller connected and the add device will turn blue then you turn on the drone and wait for the start up screen to come up are you using the large USB port on the bottom of the controller to connect to your screen device

 

[smrtalex]

At this point, I not using any of the apps. Just trying to make the connectivity between the AC and RC. Did not want to complicate with adding additional connectivity issues. Figured after I made the seemingly easy connectivity between the AC and RC, I would start the app process.

Certainly open if there is there a better way?

Also, I did power on the AC and let it sit for about 10 minutes. The AC fan did not come on and the unit was HOT!

 

[old man mavic]

you need to be registered with DJI before you can use the drone ,this requires downloading the app and following the instructions on the screen you will need a SD in the drone be on the internet and have a wifi connection you will be asked for your email address and you will have to tick agree with tick boxes during the process at the moment the drone is still registered to the previous owner i think that is why it wont connect you will need a fully charge battery in the drone and your controller before you start

 

[smrtalex]

ok.. that makes sense. Do I get the app from the Play Store and if so, which one?
DJI Go - For products before P4
DJI Go - For products since P4
DJI GO 4 -- For drones since P4

Or is there a link for app outside of the Play Store?

 

[bumper]

"Fresh water" is not pure. It contains both dissolved minerals and suspended particulate. This is why, after dunking lakes etc, it's imperative to flush and rinse with distilled water. See:
Repair of Mavic Mini.

 

[smrtalex]

"Fresh water" is not pure. It contains both dissolved minerals and suspended particulate. This is why, after dunking lakes etc, it's imperative to flush and rinse with distilled water. See:
Repair of Mavic Mini.

Completely agree! It has been awhile since this was submerged in water. I do not know if the previous owner took any other steps, like the distilled water, to flush the unit. Would it make a difference to do that now?

Thanks for your reply!

 

[old man mavic]

ok.. that makes sense. Do I get the app from the Play Store and if so, which one?
DJI Go - For products before P4
DJI Go - For products since P4
DJI GO 4 -- For drones since P4

Or is there a link for app outside of the Play Store?

DJI GO4

 

[bumper]

Completely agree! It has been awhile since this was submerged in water. I do not know if the previous owner took any other steps, like the distilled water, to flush the unit. Would it make a difference to do that now?

Thanks for your reply!

If it's not functional, it sure wouldn't hurt. Distilled water is "hungry" (like RO'd water though even more so). That means it will tend to dissolve things that were left behind by the evaporating impure water. There's no downside I can think of, so long as you don't rush things and power up before it's completely dry.

If you are mechanically "ept", there are probably videos and pictures and text on how to disassemble your drone (I used the ones from RC GEEKS to repair my M2 after slipping on icy steps and throwing my M2 into a brick wall), replaced two arm etc. The instructions for the Mini are at:

DJI Mavic Mini Teardown : What's inside?

 

[smrtalex]

DJI GO4

I downloaded the app, created an account, all good! The app started up and correct said it was the Mavic Pro with the picture of the Mavic Pro. Then it went through it process of checking versions, etc. And the ended with a blue "go fly" button on the lower right. I clicked on that and it took me to a sceen that is mostly black with "Ready to Go (GPS)" in a green tab in the upper left. That tab keeps changing to red that says "Aircraft Disconnected" and occasionly on the right side (below the signal strength icons) it says "Status No SD Card", although there is a card that is readable on my computer. The RC still just shows the battery percentage and the remote icon the the signal strength blinking.

Not sure if I am making progress or not. Any thoughts?

 

[old man mavic]

one last thing to try is to put in a new SD card ,if that fails then there is probably water damage inside the drone from its swim,which is preventing it from functioning properly

 

[smrtalex]

one last thing to try is to put in a new SD card ,if that fails then there is probably water damage inside the drone from its swim,which is preventing it from functioning properly

I will give that a try. I am suspecting it will fail, so just in case it does, would that mean I would need to replace a specific board? And if so, which one?

Thanks for all your guidance! It is truly appreciated!

 

[old man mavic]

I will give that a try. I am suspecting it will fail, so just in case it does, would that mean I would need to replace a specific board? And if so, which one?

Thanks for all your guidance! It is truly appreciated!

to be honest with you these things aren't meant to get wet inside, and although they have coatings on the boards it's what happens for those few seconds when they go in the water ,before the electrics turn off that is the biggest issue it tends to short things out, it is possible to resurrect a drone with water damage, but you need to be able to find out exactly which parts are damaged,and that requires test equipment and a good knowledge of the subject ,i really do hope you can get it flying again ,but just remember it will never be 100%reliable when water has been in it,and the cost of repair needs to be factored in as well take care my friend happy flying yours OMM

 

[SpitFire]

Here is another suggestion. Clean all electronics with 90% or greater Isopropyl Alcohol. Do not power on when wet. Blow dry parts, sorry to say you have less then 50 % for the drone to work. And, if it does it will not be reliable. Hope yours is a success story.

 

[smrtalex]

to be honest with you these things aren't meant to get wet inside, and although they have coatings on the boards it's what happens for those few seconds when they go in the water ,before the electrics turn off that is the biggest issue it tends to short things out, it is possible to resurrect a drone with water damage, but you need to be able to find out exactly which parts are damaged,and that requires test equipment and a good knowledge of the subject ,i really do hope you can get it flying again ,but just remember it will never be 100%reliable when water has been in it,and the cost of repair needs to be factored in as well take care my friend happy flying yours OMM

Completely understand and to be honest not expecting the 100% reliability. Having fun troubleshooting and diagnosing more than anything and a goal of just getting it to fly again.

I did try a brand new microSD card. Not connection. Still getting the tab keeps changing to red that says "Aircraft Disconnected" and occasionally on the right side (below the signal strength icons) it says "Status No SD Card", although there is a card that is readable on my computer. The RC still just shows the battery percentage and the remote icon the the signal strength blinking. I tried to FULLY format it via my desktop and tried. Same thing. I also tried to format it via the RC and said SD card not found. So I am suspecting the board that the SD card goes in (Main Core Board A) is bad, although I am able to see it and update the firmware via DJI Assistant 2.

Does anyone think that I should attempt anything else before I consider the board replacement?

 

[smrtalex]

Let's add a little more confusion! So I attached the RC to the DJI Assistant 2 software. I had updated it prior to the newest firmware, but it said it needed to be updated. So I updated it and it was successful to V01.04.0500. After that completed, I looked at the different tabs in the DJI Assistant 2 software and say Calibration. So I ran it. The camera was showing on the screen and I was able to move the AC around they way the calibration requested and it completed without issue, this included the cameras on the bottom of the AC as well. So I know the camera works, calibration works, etc. It appears that just the SD card slot does not work.

I also verified that the firmware on the RC is also V01.04.0500.

I did try to reconnect the AC and RC with DJI GO 4 and was not able to connect.

Is there any other testing within the DJI Assistant 2 software (or any other software) anyone might recommend to test any other aspects of either the AC or RC?