Mavic pro camera disassembly

Just a quick teardown of the Mavic Pro camera to see if any salt water corrosion made it into the camera and connector and surprisingly there was none.

So maybe camera part still fine, but no doubt the gimbal motors which were almost seized when I got it and even though I cleaned them up and they move freely now will prob show gimbal over load error as they are very sensitive to any friction and bearings prob shot.

But we shall see and the gimbal part with just motors is available as a spare part which is not expensive as long as camera lens and camera and gimbal pcb works still.

Links to other posts on this project:-

1 DJI Mavic Pro Salt water damage

2 DJI Mavic pro ESC test

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Mavic Pro ESC test

Carrying on my testing after getting hold of a insurance write off Mavic Pro Platinum that landed/crashed into the sea.

Now time to test the esc board and after much cleaning with fresh water and removing the salt deposits and then cleaning with switch cleaner any remaining residue .

I connected it up to start with a 18650 cell , as wanted to see if anything got hot or it drew a lot of amps.

All seemed fine and even the motor led came on.!

Then tested with a 2s 18650 pack and this time the dji start up esc tones came through.

Then a final test with the original mavic battery pack minus the battery pcb as thats history.

Apart from the startup tones, all 4 motors twitched as they should normally do.

One thing for sure, one of the motors has totally useless bearings as spining it in a small hobby drill attached to the shaft , its as noisey as hell the other 3 sound okay although will replace the bearings anyhow.

 

So hopefully this is a sign the esc board is possibly okay? Will be pretty amazing if it is after landing in the sea and then had its battery left in it and sat in a insurance office for god knows how long festing away.

Do wonder if this hit the sea after the motors had already stopped? as the mosfets on the esc seem to be okay. I would expect them to blow normally with motors running hitting water.

Also amazing the lipo which was reading 0.4 volts total when I got it and it charges all the way back up and seems to have decent life in it apart from 1 cell which after 2 days drops to 0 volts again, but other 2 cells stay put. Intresting as a test and nothing more, will never be used in flight again.

The gps board that I had plugged in was sending a charge to its onboard backup battery, but to see whether it actually survived will need the main board connected.

The fan motor, I already know works okay.

Next thing will no doubt be the main board and that was in the worst condition , as it has salt deposits all over it and has had lots of cleaning, especially to connectors which were badly oxidised. I dont expect this to work , but will test it anyways as long as I dont find any shorts on the boards first.

Links below to other posts on this project.

1 DJI Mavic Pro Salt water damage

 

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Onagofly

Just got hold of one of these discontinued Onagofly’s.

Just curious really as all the reviews back in the day were terrible.

Is it really so bad????

Another pic compared to Wingsland S6 for size.

Its weighs about 200 grams, so at least does not need registering in the Uk (at present)

The battery is a 800mah 2s lipo inside the quad and charged from a lead underneath into the Onagofly supplied charger.

First thing I done before flying was to load up mission planner and do the Accelerometer calibration and level one and then into the compass and do that too.

Dont know if this is needed as it might be self checking this on every boot, but done it anyways.

Risked a flight indoors, and took off okay and jumped up about 6/7 feet and then settled down a bit lower than that, but it wanders around a lot and controlling this by the phone was tricky and laggy.

The Onagofly app will not run on my iphone 6 with ios 12.4 , it crashes all the time.

So had it running on a iphone 5 with ios 10.3.4, which worked okay apart from being extremely laggy, even with video view settings set lower on app.

I did try a small tethered test outside and it took off and went to fly back into the wall , but as I had it terthered on a bit of string, was able to yank it back and then it caught up in string and ended the test.

It did show on app and via blue lights on craft it has gps lock, but as this shows at locked with 6 gps Sats, me thinks that not enough for this craft and needing at least 8+ would make more sense.

So pretty much un useable via the app as far as I am concerned, but I know there are some ppm pads inside to connect a normal rx receiver, so that is the next thing I shall try.

So onto some mods next.

 

 

 

 

 

 

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DJI Mavic Pro Salt water damage

Heres another project and that is raise a DJI Mavic Pro Platinum from the dead!

This is a Quad that crashed landed into the sea, have no idea why but my guess would be who ever was flying it ran the battery to low to get back in time?

As you can see below quite a sorry sight.

The main bottom sensor board is very salt damaged as you can see.

This was removed and run through clean warm water and then dryed off and cleaned more with isopropyl and looks better at least now:-

The esc/imu board did not look too bad apart from a tiny bit of salt corrosion around the fets. If the motors were running when it hit the sea, they will be totally shot.

The battery connector was very green and corroded, which is what I would expect as the reaction of hitting water , especially nice conductive salt water.

2 of the motors were seized and although now freed up with some oil into bearings and windings, these would need to be stripped cleaned and new bearings.

The wifi board at the back was not too bad, slight salt deposits and the gps module was also not too bad.

The gimbal was okay on 2 of the motors but seized on 1. A bit of cleaning and oil and they are now free. The camera is sealed and hence unless connector badly corroded is prob fine.

The gimbal board though got a fair bit of corrorsion on the connectors and doubt that will work again.

The battery as expected was dead. Once apart…..

Which taking these batts apart is a royal pain in the butt!!

After removing the battery pcb totally and measuring the pack, it read 0.4 volts total.

Selected nicad on the charger and slowly at 0.1 of amp started to see if it would take any charge, it slowly rose up and once it got near 9 volts, I switched to charging the pack via the lipo setting at 0.1 amp charge rate. I left it charging with a fan blowing on the pack to keep it cool. End result was it stopped charging at 12.6volts. I had to turn off the balance charge as I was charging direct to the 3 cells.

Also on a safety note, I have a metal tin close by and also was in room all the time to keep a eye out for the pack starting to puff up and turn into a fire.

(Would not advise this unless you 100% know what you doing, once cells gone this low charging can be dangerous and dont charge at anything but min charge levels.)

Not tested the fully charged pack, but I expect the cells to fall through the floor with any kind of load.

Question I hear people ask…

Is this worth a rebuild???

Really depends on how much of the quad electronics , if any still works…

Almost certainly will need 2 user parts to make it economically viable.

As using all new parts and new battery and new controller = not worth it.

Will add posts on the journey to get this to work again….

Some other pics, more cleaning required before can test what if anything still works 😉

Well the internal fan still works 😉 Although a pic wont really show that, but hey thats the first part that works ticked off list!

 

 

 

 

 

 

 

 

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DJI Mavic Mini Different models

Need to bear this in mind if you are buying a DJI Mavic Mini!!!!.

There are different versions depending on what country you buy it in!

As I read all new dji models will be hardware power locked CE or FCC etc.

If in the Uk like I am , we are stuck with the low power CE version. So about only 500 metres.

But if you buy out of the EU , you get the FCC version and about 2,500 metres.

Big issue I have is if you buy one in the EU and travel abroad in FCC countries , you are stuck with the CE , as it cant be changed to FCC unlike the older dji models that the app decides what mode to put you in, depending on whether you in CE or FCC area.

This puts me right off a Mavic Mini now, as when out of country I would be stuck in low power version. Seems crazy for a travel drone, that you stay stuck like that.

So no point in me aiming to get ones of these while I am in the CE zone.

Info and part numbers on DJI Mavic Mini models

FCC version:- Model MT1SS5      – 5.8 GHz: <30 dBm (FCC); <28 dBm (SRRC)

CE version:-   Model MT1SD25   – 2.4 GHz: <19 dBm (MIC/CE) 5.8 GHz: <14 dBm (CE)

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