Got hold of a damaged Parrot Bebop 2 , suffering from landing in the sea.
Judging by the state of the boards and motors, I assume its been sitting around after it’s dip in the sea for quite some time.
First thing was to totally strip down everything and then wash all the boads and let them soak in warm distilled water to try and disolve the left over salt water damage.
Then after this was to dry the boards off and them drop them in isopropyl for a few hours.
After this, let the boards dry out and then inspect and still parts around some of the smaller chips that had bad corrosion.
Used a small brush and a combination of switch cleaner and then washed the main board again with washing up liquid and gently rubbed away and then dryed and back into the isopropyl for a while.
Then coated the bad areas around the corroded chips with some solder flux as that may help and then will probably use a heat gun and more flux to clean the chip up.
But at present it looks so fragile, that part can wait while I check the board for shorts.
The battery on this was left plugged in, which is a shame the previous owner did not leave it removed.
The board had a short on the incoming main power line, and the lipo that came with it was totally reading 0 volts.
At this stage, looking like it will need a new main board which is uneconomical of course as the board is like £249.99 in the uk or $324.99 in the USA.
Also all the bearings on the motors are gone and 2 motors the bearings totally seized and so they would also need to be replaced and those motors should be fine.
But as the main board is pretty much a trash job, it cant do any more harm to have a play!
So first off wanted to see if I can get some clue where the sort was so connected up a small 1.2volt battery to main board input and quite quickly drained that down. Not enough current for anything to get warm.
Then applied 2.4 and then 3.6 and killed them pretty quick, these were only normal dry cells.
So next connected up a 18650 battery at 4.1 volts charged and it was only slighty draining down, but done a few measurements and had that 4.1 volts at 3 of the 4 motor wires.
I am fully expecting the mosfets to have died landing in water.
I dont know history of why it landed in the water, I presume low battery and it when into auto land.
Thats as far as I have got thus far into this experiment.
4 motors are salvageable once new bearings fitted.
Just looks wise the gps board looks like it might be okay as no corrosion on it( I did remove the small backup battery on it)
The main Camera looks sealed and maybe water did not make it into base, but have to assume theres a good chance that is history too.
Downward facing position hold camera again looks ok, but again have to assume it trash.
The ribbons on the board connecting various items all badly corroded.
All in all this confirms what we already really know, if a quadcopter lands in water and even more so salt water, you have to get the battery out ASAP and DO NOT leave the quadcopter to dry out.
You must either strip it down and wash it with distilled water and dry and clean off or get it someone who can do this for you.
Leaving it as this previous owner did will pretty much write off the chance of repairing it at a cost effective price.
Now I am going to ramp up the current to see what gets hot……