Tello ended in salty ocean water, dead - reporting repair attempt [UPDATE2: it flys!]

[w84death]

Long story short after hitting a big rock my drone ended in the very shallow water at the beach.

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He floated! (it was like 15cm deep but I was impressed that he has this ability). Then we started the rescue mission. But right before we get to the drone it stated his engines and tried to fly.



Turning it off helps. I soaked it at spot and wanted one more shot so I just turn on for a open to check whats the status. It's not good - Tello starts and immediately runs 2 motors in different speeds. I turned it off and removed the battery. I put it on the sun and it dried out for the rest of the day.

Now I see that the chips looks promising (at last capacitors) but everything i coated in salt. Here is a few close shots.





I'm an IT guy and don't have tchat much experience with electronics. Can you help me with cleaning the board? I will go to the shop for a small screwdriver to remove all Tello shell and get to the bottom of the board also. I just need to know what else should I get. Some detergent/alcohol probably but exactly what?

 

[umanbean]

Ugh! That looks bad. And unfortunately it's too late for anything you could have done to prolong the life. The water has dried leaving salt and sand behind. Salt is very corrosive, and once it comes in contact with electronics, the quicker you wash it off the more life will be left in the device... but you can never stop the corrosive effects over time.

It's too late now, but here's what you should have done:

• Immediately -pull the battery.
• Immediately -thoroughly wash / rinse the Drone with fresh water - preferably distilled. In fact, without the battery in it you can throw it in a bucket or a bowl of fresh water and leave it for a while or * rinse it thoroughly under a sink faucet. (* now that I think about it, leaving it submerged might not be a good idea because water might seep into the camera assembly)
• The battery will need rinsing off also but don't leave it under water.
• If necessary, bottled drinking water can be used on-site instead of distilled.
• The more thoroughly you rinse it - before it dries the first time - the better.
• Let it dry completely, forget that bag of rice BS - that's just internet myth. Either leave it sitting around for several days or put a fan on it or use a hair blow dryer. Make sure it's completely dry inside, and the motors too, before you insert another battery.
• Insert a battery, preferably a fresh one, cross your fingers, hold your breath, and power it on.
• With any luck you'll get to fly for a good while longer before the corrosion eats through the traces on the circuit board.

Did you say you were an IT guy?

Sorry for your loss

 

[Achin]

If I were you,I wouldn't take tello to the beach where gusty winds are present and also if it is so then I wouldn't fly it over rocks which contains salty water beneath it.Sorry for your loss brother but better to take it to authorized service centre.

Sent from my CPH1729 using Tapatalk

 

[TelloCarl]

Aw, it does look terminal. When mine went missing it was battery out, covers off and straight in front of a fan after drying using kitchen roll.

 

[w84death]

I bought Tello to do stupid things now and learn. And if something bad hapens then heck it's 100 euro. Also I have a backup unit with me.
And yes - I will not fly around rocks anymore I learn my lesson now I will concentrate on the main purpose - photos and cine clips.

I will try to clean it up and report what I got. In the worst case scenario I will have a lost of spare parts for my other drone.

 

[Gadicarv]

I bought Tello to do stupid things now and learn. And if something bad hapens then heck it's 100 euro. Also I have a backup unit with me.
And yes - I will not fly around rocks anymore I learn my lesson now I will concentrate on the main purpose - photos and cine clips.

I will try to clean it up and report what I got. In the worst case scenario I will have a lost of spare parts for my other drone.

Well, luckily you got another one so, yes just continue taking photos and doing that stuff.
p.s you take good photos

 

[w84death]

I cleaned the dead drone in hot water. It now looks way better now. Tomorrow I will test it.



@Gadicarvil7 thanks I'm a hobbys (few times proffesional) photographer that just discovered Tello as a flying camera! (videos are meh..)

@umanbean Thanks for instructions. I can do assembly but I failed with salt water yeah..

 

[Flydrone]

I know the electronics well enough and I can advise you to wash the logic board with an isopropyl alcohol solution and a toothbrush ... the best thing to do is an ultrasonic washing cycle with antioxidant solution.
I have already done this type of ultrasonic cleaning on the logic boards of smartphones and I have obtained excellent results.
the lower part of the logic board is also probably oxidized and should be dismantled as much as possible to remove oxidation.

 

[w84death]

UPDATE



I cleaned up the drone main board with screen cleaner and soft brush. After a while boot it up. And we have a partially working drone!





What works:

• when it boots it boots normally
• wifi connection
• camera
• all gyros
• Why in land position: probably IR sensor but it shows negative meters when getng the aircraft up and positive when going down (by my hand hoovering in the air). It succesfully zeors meters when I stoped it in place for a moment.

What doesn't work:

• sometimes it can not boot (starts and turns off after few colorful blinks)
• TelloFPV: Error 74 (if I recall correctly)
• Tello official: IMU error "try to calibrate"

I did one callibration, it went ok but then it has problems booting up. When finally boots the error stays the same.



I will do a more look at the board later and probably do one more clean up. And more precise IMU callibration. Overall I'm super impressed how many systems still works fine

 

[Flydrone]

Error 74 if I'm not mistaken is a camera error.
try to gently remove the two drops of glue on the contact and clean the contacts of the card and the camera connector and reassemble everything gently making sure that the connector is well inserted in its seat by pressing lightly on it, now you can put two drops of glue in hot on the connector.

for shutdown, try removing the shield under the heatsink and cleaning the contact pins of the n: (A) ACTIVE 8846QM chip responsible for the power supply and remove any oxidation.
Next you will need to put thermal paste on the chip.

 

[RyanR]

Distilled water does not conduct electricity. Good for cleaning electronics!

 

[w84death]

Today after a long wait I take the drone to the bench. I analyze everything and there was one super small capacitor that got loose. I moved it to the right position but it doesn't look good.
It's so small I don't have event the hardware to fix that. Not to say i don't know what capacitor it is.



I moved it to fit it's original position. And it works! I fly the drone! But not for so long. I landed safely. A needed to put rubbers back in (I wanted to just check if it works or not) I probably moved this capacitor and it's back to IMU error.

Now as I try to move it back I... lost the capacitor. It disaperad on my eyes. Jump and it's gone.


Anyone know what kind of cap can this been or how can I fix that?

 

[volate!lo]

phew.... buy one with broken shell, motors or camera. Should be less than $20