Professional P3P dropped into the sea

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Hi everyone,
my P3P fell into sea water, I immediately recovered and washed it in fresh water.
The battery is gone, while the drone, after being dried for 3 days, turns on but has the following problems:
- no images in the app;
- the camera controls don't work;
- the micro SD isn't recognized;
- engines don't start and ESC status error appears in the app;
- the app shows the battery voltage but not the voltage of the cells.

All other things seem to work properly:
IMU and compass OK;
GPS OK;
Gimbal OK;
Vision Positioning System seems OK.

I opened the P3P and checked all boards for salt problems but it was enough good. I washed all again with demineralized water.

What can be broken?
Is it worth repairing?

Can anyone help me?

In the images below the problems encountered.

1568899456744.png
1568899483927.png
1568899509723.png
 
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Thanks Meta4.
I know it, for this reason I used also isopropyl alcohol to eliminate all salt residues.
I'm not able to make a diagnosis of what can be broken and I would like to avoid changing parts at random.
 

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I'm not able to make a diagnosis of what can be broken and I would like to avoid changing parts at random.
Not much that can be done with a salt water soak. You can clean all you like. The corrosion process begins immediately on contact, and once that starts, it is basically too late. Salt water on electronics is basically acid. Especially so on copper, and or sliver solder. I wish you luck, but I would not hold out much hope for any sort of longevity, even if you should locate where the issue is.
 
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Demineralized water ASAP is the best way to handle such situation, you did good.

So it looks like there are two issues:
1. with ESC Center Board - the issue which makes it show "ESC Status Error".
2. with Gimbal Top Board - the issue which makes SD not recognized, and no video feed.

ad 1.
ESC Center Board is quite easily available to buy; for diagnosing - download Flight Log from DAT and check which ESC is an issue. Then try to find damage in that part of the board. Details:
Fix ESC Status Error on Ph3 Pro Ph3 Adv or Ph3 Std

ad 2.
Gimbal Top Boards are not that easy to get, and usually more expensive - so would be nice if it could be repaired. As a start, check if all all pads marked with voltage have said voltage on them, using multimeter. The board receives 12V and has its own regulators which make 5V, 3.3V etc. from it. Salt affects high voltage wires much more, so there's a high chance the issue is somewhere between 12V regulator and the second stage regulators. Hopefully the bigger chips were not affected.
I have a graph for similar case, though some steps don't make much sense in your case:
Fix no video feed / black screen / no image transmission / no FPV on Ph3 Pro
 
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Demineralized water ASAP is the best way to handle such situation, you did good.

So it looks like there are two issues:
1. with ESC Center Board - the issue which makes it show "ESC Status Error".
2. with Gimbal Top Board - the issue which makes SD not recognized, and no video feed.

ad 1.
ESC Center Board is quite easily available to buy; for diagnosing - download Flight Log from DAT and check which ESC is an issue. Then try to find damage in that part of the board. Details:
Fix ESC Status Error on Ph3 Pro Ph3 Adv or Ph3 Std

ad 2.
Gimbal Top Boards are not that easy to get, and usually more expensive - so would be nice if it could be repaired. As a start, check if all all pads marked with voltage have said voltage on them, using multimeter. The board receives 12V and has its own regulators which make 5V, 3.3V etc. from it. Salt affects high voltage wires much more, so there's a high chance the issue is somewhere between 12V regulator and the second stage regulators. Hopefully the bigger chips were not affected.
I have a graph for similar case, though some steps don't make much sense in your case:
Fix no video feed / black screen / no image transmission / no FPV on Ph3 Pro
Pretty solid advice, right there!
 
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Being in the same situation, I would buy a new drone. Sorry.
 
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Washing with water or alcohol doesn't stop the corrosion, it just slows it down. There are too many connections and contacts to have any hope of a long term fix. You can probably get it to fly again, but it will never be reliable.
 
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Hi everyone,
my P3P fell into sea water, I immediately recovered and washed it in fresh water.
The battery is gone, while the drone, after being dried for 3 days, turns on but has the following problems:
- no images in the app;
- the camera controls don't work;
- the micro SD isn't recognized;
- engines don't start and ESC status error appears in the app;
- the app shows the battery voltage but not the voltage of the cells.

All other things seem to work properly:
IMU and compass OK;
GPS OK;
Gimbal OK;
Vision Positioning System seems OK.

I opened the P3P and checked all boards for salt problems but it was enough good. I washed all again with demineralized water.

What can be broken?
Is it worth repairing?

Can anyone help me?

In the images below the problems encountered.

View attachment 114577View attachment 114578View attachment 114579
I work on laptops and it only takes a millisecond of exposure to short out. I'm betting the board it toast. No amount of cleaning with water is going to fix it. maybe you can find a board online somewhere. Sorry for the bad news.
 
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Washing with water or alcohol doesn't stop the corrosion, it just slows it down.
Any sources for that? Especially for the corrosion caused by alcohol?
Because this is against scientific knowledge.

There are too many connections and contacts to have any hope of a long term fix.
How exactly the amount of connections is a factor? Again, any scientific background?
By "long term" do you mean years? because if 10 years, any Phantom is likely to malfunction. With water & alcohol or not.

If the device gets damaged after fix, something was done wrong: not all the salt was removed, not all the water was dried, or not all the damage on the board was fixed. If the device was handled properly, there's nothing to worry about.

You can probably get it to fly again, but it will never be reliable.
It is one thing to have your own opinion, and another thing to happily spread disinformation. No. That's just not true at all.

If electronics, after contact with water, is removed from any power sources, then properly cleaned (ie. with demineralized water, or at least fresh water), then properly dried (it might require some help for narrow gaps to dry), it becomes the same dry electronics it was before.
It might not work without some service, some chips may even be fried, but there is no hidden magic which was washed away.


Actually, if the device was disconnected and cleaned up fast enough, usually only power supply circuits are damaged by water. Because salt (and other ions in water) are oxidizing copper with speed proportional to voltage difference, often only highest voltage parts are destroyed, and the sensitive electronics is not affected. In case of Phantoms, direct battery voltage and stabilized 12V supply lines are usually the only damage.

There is more depth into it, for example if the device is not designed keeping in mind all the engineering practices, water may short power line to a sensitive signal line, ie. send 12V to 1.2V login input. That will fry the affected chip. But 1 - engineers should avoid this by placing ground line between power and signal lines; 2 - it's still one damaged chip which can be just replaced.

Dji is not making magic. They're taking pre-made chips from real manufacturers and just placing them on their boards. They're using "application example" schematics from the chip manufacturers. That's not some god knowledge inaccessible to mere mortals. It requires a few years of studies and practice, but anyone could do that. (though it would take quite long time for one person to completely design such drone..).


I'm betting the board it toast. No amount of cleaning with water is going to fix it. maybe you can find a board online somewhere.
Something is definitely fried. And time spent on fixing a board, if you're not a specialist, usually isn't worth it.
Then, some things you do not because it is optimal solution, but for the journey.
And for the experience you're getting on the way.
 
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If your drone falls into a fresh water lake, river or pond - you can possibly dry it out and be fine. Not always, but many people have and continued to fly for years with no issues. The battery must always be replaced, however.

If your drone falls into saltwater - it's toast. Time for a new drone.
 
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I agree with all the posts. Keep in mind, when these DJI drones crash into water, they are still trying to fly, power on against the heavy resistance of water. It overloads the ESC's. Unfortunately, the P3 models have the ESC's integrated into the mother board. Just replace it.

The camera is another story. The gimbal motors and circuit board contacts are bare metal and will corrode. The circuit boards themselves have been sprayed with a protective coating, but it doesn't really matter. I have been able to save fresh water crashed drones, but avoid salt water like the plague. If the upper main circuit board in the camera tests good, the rest of the gimbal can be repaired with good components.
 
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HWB

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Build a raft, put in the raft, set fire to the raft and push it out to sea.
 
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Demineralized water ASAP is the best way to handle such situation, you did good.

So it looks like there are two issues:
1. with ESC Center Board - the issue which makes it show "ESC Status Error".
2. with Gimbal Top Board - the issue which makes SD not recognized, and no video feed.

ad 1.
ESC Center Board is quite easily available to buy; for diagnosing - download Flight Log from DAT and check which ESC is an issue. Then try to find damage in that part of the board. Details:
Fix ESC Status Error on Ph3 Pro Ph3 Adv or Ph3 Std

ad 2.
Gimbal Top Boards are not that easy to get, and usually more expensive - so would be nice if it could be repaired. As a start, check if all all pads marked with voltage have said voltage on them, using multimeter. The board receives 12V and has its own regulators which make 5V, 3.3V etc. from it. Salt affects high voltage wires much more, so there's a high chance the issue is somewhere between 12V regulator and the second stage regulators. Hopefully the bigger chips were not affected.
I have a graph for similar case, though some steps don't make much sense in your case:
Fix no video feed / black screen / no image transmission / no FPV on Ph3 Pro
Hi quaddamage, thanks a lot for your advices. I have started the diagnosis for the "ESC Status Error" and in the .DAT file I have found in the column "esc3_status" the value 18 and in all the other esc3 columns only the value 0, while in the other "escX_status" (X=1,2,4) I have found the 0 value and different value in the other escX columns.
From this situation can I understand if the problem is in the motor or on the center board?
In the workflow the resistance test of the motor reports ??? Ohm. There is a correct Ohm range? What is it?
 
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I have started the diagnosis for the "ESC Status Error" and in the .DAT file I have found in the column "esc3_status" the value 18 and in all the other esc3 columns only the value 0, while in the other "escX_status" (X=1,2,4) I have found the 0 value and different value in the other escX columns.
From this situation can I understand if the problem is in the motor or on the center board?
Damaged ESC is more likely, but I can't tell anything from the value. We don't know what these flags mean. You at least know that there is only issue with one ESC, and in which part of the board it is.

In the workflow the resistance test of the motor reports ??? Ohm. There is a correct Ohm range? What is it?
I just couldn't remember the correct value when creating that graph. I only diagnosed ESC twice I think.. Get the correct value from other ESCs. You may also post it, and I will update the graph.
 
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Damaged ESC is more likely, but I can't tell anything from the value. We don't know what these flags mean. You at least know that there is only issue with one ESC, and in which part of the board it is.



I just couldn't remember the correct value when creating that graph. I only diagnosed ESC twice I think.. Get the correct value from other ESCs. You may also post it, and I will update the graph.
Ok! It is already great to have limited the area where the problem may be.
I will start to test the motor, I notice it is a bit harder to rotate than the other.
I will tell you the values I will measure.

Thanks
 
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Damaged ESC is more likely, but I can't tell anything from the value. We don't know what these flags mean. You at least know that there is only issue with one ESC, and in which part of the board it is.



I just couldn't remember the correct value when creating that graph. I only diagnosed ESC twice I think.. Get the correct value from other ESCs. You may also post it, and I will update the graph.
Hi quaddamage, yesterday I had time to check the M3 esc error.
I have followed the flow chart and
I checked the resistance of every pair of M3 motor wires and they are 0,08 Ohms. The M1 has same values. I'm sorry but I could not measure inductance.
Then I tested the resistance between battery and motor pads.
I had always read 46,5 kOhm between Vcc (+) and motor pads and 41 kOhm between ground and motor pads. In the M1 I found the same values.
I also tried to reverse the motor and checked the DAT file. The non zero value is always in esc3_status.
So I think the MOSFETs are ok.
How can I check if the problem is in the microcontroller or in the motor drive?
 
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How can I check if the problem is in the microcontroller or in the motor drive?
This is beyond my knowledge, unfortunately. The ESC errors I had, I was able to fix with either chips reflow, MOSFETs replace or reflow of FC daughterboard connection.

I'd go with the thinking:

If your micro-controller talks to FC board (and it does, because only specific bits in ESC status were set - otherwise there would be 0xff or -1), then it seem to be working. So it is likely working properly - it boots, it uses its UART interface, it doesn't crash. There could be, in theory, damage to its interface to motor driver, but it's unlikely - HW issue would cause instability, and weird effects in FC log.

So blame motor driver. the micro-cotroller works fine.

Here's a video I found; these guys seem to be replacing every chip in the faulty ESC with components from donor board:

 
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This is beyond my knowledge, unfortunately. The ESC errors I had, I was able to fix with either chips reflow, MOSFETs replace or reflow of FC daughterboard connection.

I'd go with the thinking:

If your micro-controller talks to FC board (and it does, because only specific bits in ESC status were set - otherwise there would be 0xff or -1), then it seem to be working. So it is likely working properly - it boots, it uses its UART interface, it doesn't crash. There could be, in theory, damage to its interface to motor driver, but it's unlikely - HW issue would cause instability, and weird effects in FC log.

So blame motor driver. the micro-cotroller works fine.

Here's a video I found; these guys seem to be replacing every chip in the faulty ESC with components from donor board:

Thanks.
I saw that there some pads near the motor drive. I found that they are for diagnosis but I haven't found the values. When I have time I will try to compare the values between M3 and M1 values.
In the meantime I'm looking for a ESC center board
 

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