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Mini 2 sunk in swimming pool, still alive and flying but disconnecting, what now?

thelazydesigner

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Hello there,

so here's the thing: after 3+ years of perfect flights with DJI Spark in every possible risky conditions, my new Mini 2 decided to crash on a wire above a swimming pool and take a deep dive on its third flight! Do you think we could call this "excess of self-confidence"? :rolleyes: Nice thing to add: no DJI care refresh this time!

Unfortunately drone was not recording, reached bottom of the swimming pool (2 meters) and stayed there like 1 minute until getting saved. For the whole time it never stopped sending video feed and did not power down! Was still connected when I removed the battery. I tried to dry it ASAP with an air compressor and left whole day drying non in direct sunlight.

The battery developed blue-ish oxidation signs on connectors and never got used it again (days later: does not charge anymore giving a over-voltage error in charger - not surprising)

We tried flying the drone after 1 day and.. It was working! Motors OK, gimbal OK, camera OK, recording OK, GPS ok, connection seemed ok, stability ok etc...

Then we left it to dry even more but after 2 weeks flight is not stable anymore: drone is disconnecting from remote, even when not flying, flight has become dangerous as returning home is happening almost every minute and you know without obstacle sensors it could actually go committing suicide..

So since I do not have DJI Care this time I disassembled the top shelf to find out a lot of blue oxidation signs are on what i think is the ERC board (see photo).
Anyway if this is the board controlling motors they still work very fine. I guess there is more damage around the transmission system and maybe GPS.
I still have to disassemble the bottom main board, as seems more complicated.

Need some help from you:
  • Do you know where are the sync electronics and antennas located? Are there cables/connectors I could try to clean?
  • Do you suggest going on all electronics with Isopropylic alcohol or WD-40?
  • Do you think I should try to save this guy or time will bring more and more damage and won't be worth the effort?
If you are asking "why didn't you ask DJI" well let me say that Italian service is not that helpful and unless you have a Care refresh they won't repair anything, they even told me to buy a whole new kit as they won't sell me a "drone only" replacement part... So saving the guy is now a personal hobby while I'm probably going to buy another one as well.

Any help really appreciated!!
 

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The battery is toast straight up, dispose of that properly.
Sorry to say, I believe you could never trust this drone again in the sky, even if you can get it connecting again reliably.

DJI will repair drones, but NEVER touch a drowned bird, whether salt or fresh water.

Do you know if it was a salt or chlorinated pool ?
 
Hello there,

so here's the thing: after 3+ years of perfect flights with DJI Spark in every possible risky conditions, my new Mini 2 decided to crash on a wire above a swimming pool and take a deep dive on its third flight! Do you think we could call this "excess of self-confidence"? :rolleyes: Nice thing to add: no DJI care refresh this time!

Unfortunately drone was not recording, reached bottom of the swimming pool (2 meters) and stayed there like 1 minute until getting saved. For the whole time it never stopped sending video feed and did not power down! Was still connected when I removed the battery. I tried to dry it ASAP with an air compressor and left whole day drying non in direct sunlight.

The battery developed blue-ish oxidation signs on connectors and never got used it again (days later: does not charge anymore giving a over-voltage error in charger - not surprising)

We tried flying the drone after 1 day and.. It was working! Motors OK, gimbal OK, camera OK, recording OK, GPS ok, connection seemed ok, stability ok etc...

Then we left it to dry even more but after 2 weeks flight is not stable anymore: drone is disconnecting from remote, even when not flying, flight has become dangerous as returning home is happening almost every minute and you know without obstacle sensors it could actually go committing suicide..

So since I do not have DJI Care this time I disassembled the top shelf to find out a lot of blue oxidation signs are on what i think is the ERC board (see photo).
Anyway if this is the board controlling motors they still work very fine. I guess there is more damage around the transmission system and maybe GPS.
I still have to disassemble the bottom main board, as seems more complicated.

Need some help from you:
  • Do you know where are the sync electronics and antennas located? Are there cables/connectors I could try to clean?
  • Do you suggest going on all electronics with Isopropylic alcohol or WD-40?
  • Do you think I should try to save this guy or time will bring more and more damage and won't be worth the effort?
If you are asking "why didn't you ask DJI" well let me say that Italian service is not that helpful and unless you have a Care refresh they won't repair anything, they even told me to buy a whole new kit as they won't sell me a "drone only" replacement part... So saving the guy is now a personal hobby while I'm probably going to buy another one as well.

Any help really appreciated!!

Wow you got lucky, after a fashion! I live on a marshy saltwater peninsula and have had more than my share of damp, wet, soaked electronic components. WD-40 and alcohol are excellent water displacement vehicles. However, in my experience nothing beats immersing a drowning victim in a generous amount of distilled water(sans battery) for a minimum of 24 hours(with the hope any residual contaminates will dissipate/dissolve/wash out), followed with air drying(no compressed air, too dirty and/or wet). Then packing the affected part into a container of clean dry rice. Allow the rice 4 to 6 days to perform its magic.

May the force be with you!
 
Based on how many times we submerged the Mini 2 underwater , you will most likely need to replace the Mother board and the ESC module as they are the weak link.

Phantomrain.org
Gear to fly your Mini 2 in the Rain and land on the Water.
 
Most swimming pools use chlorine. I suspect that time, natural humidity and chlorine residue have taken its toll.
Check out drone-retriever.com for insight into what to do after a water event.
 
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Do you know if it was a salt or chlorinated pool ?
Chlorinated water, pretty fun it was almost good after 6 hours of drying.. almost a miracle, but no more actions probably led to some corrosion disaster..

but considering there's a connection issue only..who knows.. maybe there's an antenna connector somewhere....
 
Chlorinated water, pretty fun it was almost good after 6 hours of drying.. almost a miracle, but no more actions probably led to some corrosion disaster..

but considering there's a connection issue only..who knows.. maybe there's an antenna connector somewhere....

Could be right regarding time after drowning in chlorinated water.

Probably too late now for this drone, but best advice is on the drone retriever site, Very bottom of page . . .

WHAT ACTUALLY HAPPENS TO A DRONE AFTER A WATER EVENT​

This is what I'd do in some cases of water crash / decent splash, but note, I take nothing when flying often over water.
I know and accept the chances I'd fly the drone again in case of such a crash is so slim, it's not worth bothering.
Some of the following is different to Drone Retriever advice (battery, oven use).

Remove battery immediately (to be discarded properly), wash / soak drone asap with copious amounts of fresh or preferably distilled water immediately, drain water off and flush thoroughly with 99% isoprolyl alcohol, allow to evaporate and dry out.
Isopropyl disperses water fantastically, has no effect of anything electronic/ plastic, and leaves no residue.
Not many would keep say a 4lt (gallon) bottle handy though.
Carefully test drone out in suitable location for a period of time, maybe trust can be re-established.

I still say long term any drone having been immersed for more than say 1 seconds, is asking for trouble later with electronics.
Maybe a quick splash down in fresh water, stream etc, but needs to be opened up is some cases and the cleaning done if necessary.
 
Wow you got lucky, after a fashion! I live on a marshy saltwater peninsula and have had more than my share of damp, wet, soaked electronic components. WD-40 and alcohol are excellent water displacement vehicles. However, in my experience nothing beats immersing a drowning victim in a generous amount of distilled water(sans battery) for a minimum of 24 hours(with the hope any residual contaminates will dissipate/dissolve/wash out), followed with air drying(no compressed air, too dirty and/or wet). Then packing the affected part into a container of clean dry rice. Allow the rice 4 to 6 days to perform its magic.

May the force be with you!
Bahahaha, I can’t believe people still believe and promote this “put it in rice” thing. It doesn’t work and never has. It been proven over and over and over. Rice doesn’t pull moisture of of the air. You are wasting your time.
 
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Bahahaha, I can’t believe people still believe and promote this “put it in rice” thing. It doesn’t work and never has. It been proven over and over and over. Rice doesn’t pull moisture of of the air. You are wasting your time.

When was the last time your work was published in a scientific journal?



"Before engaging mouth be certain brain is in gear"
 
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When was the last time your work was published in a scientific journal?



"Before engaging mouth be certain brain is in gear"
I see you picked one article out of many that sides with using rice. There are many that say and prove otherwise. Also, set some rice on a plate next to a bowl of water. It’s never going to absorb that water.
I have been repairing electronics for 30 years. I have seen a lot of wet phones come in that have been “sealed in a bag of rice for a couple days”. Notice I said they were wet. Because they sealed them in a bag where the moisture could not evaporate. The best recommendation is to remove the battery as soon as possible, if possible; then disassemble the electronic device as best as you can, use isopropyl alcohol to dissipate the water and then set it in front of moving air, like a fan.
But please, buy all the rice and put it in a bag as this has worked in all your years of electronic repair. ??
 
I see you picked one article out of many that sides with using rice. There are many that say and prove otherwise. Also, set some rice on a plate next to a bowl of water. It’s never going to absorb that water.
I have been repairing electronics for 30 years. I have seen a lot of wet phones come in that have been “sealed in a bag of rice for a couple days”. Notice I said they were wet. Because they sealed them in a bag where the moisture could not evaporate. The best recommendation is to remove the battery as soon as possible, if possible; then disassemble the electronic device as best as you can, use isopropyl alcohol to dissipate the water and then set it in front of moving air, like a fan.
But please, buy all the rice and put it in a bag as this has worked in all your years of electronic repair. ??


Your cognitive skills are minimal that's for certain. When did I say to put anything wet into a bag of rice?
 
Your cognitive skills are minimal that's for certain. When did I say to put anything wet into a bag of rice?
K.
Give it up. I’m right, your wrong. Have a great week. You learned something new today about how to treat water damaged electronics. You are welcome.
 
I see you picked one article out of many that sides with using rice. There are many that say and prove otherwise. Also, set some rice on a plate next to a bowl of water. It’s never going to absorb that water.
...
I don't have a dog in the fight, but it will absorb that water if you put the rice on the water. A towel next to a plate of water isn't going to absorb that water either.
 
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Fresh water (distilled if possible) rinse well, flush with Isopropyl even 'weller', leave to dry in a warm humidity free spot.
This seems to be the advice given by techs that deal with this sort of thing for a living.

I can see rice might be better than nothing, but to work at all you'd have still do the water rinse, paper towel wrap the drone to keep the fine rice dust out, then ziplock bag it and place in a warm place to allow heat to evaporate the water in the bag for the rice to absorb.
My personal thought is you will be mostly fogging up the inside of the bag, and the moisture is still in the bag in the rice, not really drying it out totally.

Silica Gel desiccant in a sealed Tupperware box is supposed to be a lot better, but again the gel still holds the water, may need changing to complete the job.

How much better is it to get the dirty water out, get the fresh water out immediately with Isopropyl ?
Then allow that to evap completely (Iso is very fast to evap) in that warm place.
 
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I don't have a dog in the fight, but it will absorb that water if you put the rice on the water. A towel next to a plate of water isn't going to absorb that water either.
Exactly. The water has to touch the rice. Just like the towel has to touch the water. If the water is inside the mini, it’s not going to magically get absorbed into the rice.
 
K.
Give it up. I’m right, your wrong. Have a great week. You learned something new today about how to treat water damaged electronics. You are welcome.
He learned your rude and would walk away.
You’ve stated your opinion so that’s all that’s needed.
 
"Do you know where are the sync electronics and antennas located?" Probably in the vertical portions of the landing legs. If like the Mavic 2 Pro mentioned below) possibly with a soldered connection in the leg and a gold coated clip on connection in the drone's body

I have just dismantled a Mavic 2 Pro that was in the sea for a few days. The corrosion was/is staggering.
In places. Especially near or around steel screws the light metal alloys corrode like billy-o.
The sensors that look to the sides, rear and upwards are mounted on a frame of some sort, that frame no longer exists, it's mush.
I'd guess much of the staggering corrosion I found stems from electrolytic corrosion.

Many of the clip in connecters (male) of the ribbon cables delaminated and some of the females lifted off their circuit boards.
 
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