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Drowned drone CPR

Discussion in 'Phantom 2 Vision + Discussion' started by markintheworld, Apr 18, 2016.

  1. markintheworld

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    My P2v+ took a dive in the Hudson River this past weekend - went haywire on takeoff, flashing red and out of control, and splashed down !!!spectacularly!!! 75 ft offshore...

    My heart hurt. That was a $1000+ splash...

    I waited out the tide, and recovered the upside-down bird from the tidal mud - battery was knocked loose upon impact with the bottom - shook her out and took her home. Opened the shell when I got home and dried her out with a hair-dryer....She was in 3' of water for 3 hrs, In the mud flats, but was remarkably clean.

    Disassembled gimbal and buried it in rice, going to deal with that later...

    Inspection of the bird revealed some zap marks on the speed controllers; my suspicion is that these are most susceptible to shorting out due to the high current traveling through them - sure enough, when I powered up after 2 days of drying out, the right rear speed control BURST INTO FLAMES. Terrifying. I guess I might replace that. (See attached pic)

    My questions for discussion as I proceed with my forensic examination:

    What other electronics are most highly susceptible to water damage? I am visually inspecting for evidence of electrical shorts, and I see limited damage (maybe 1 site on main board)...Just wondering if it is worth replacing the ESCs ($20 ea) and then proceeding with diagnostics, or if I'm barking up a dead tree...
     

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    #1 markintheworld, Apr 18, 2016
    Last edited: Apr 18, 2016
  2. xgaul

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    Lol @ rice. Why do people continue to think that works?


    Sent from my iPhone using PhantomPilots mobile app
     
  3. N017RW

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    People have had success doing it.
    Hard to say it didn't help OR that it makes no difference since there's no 'control' to the experiment.
     
  4. xgaul

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    All rice does is absorb liquid it doesn't do [EXPLETIVE REMOVED] for any of the board damage.


    Sent from my iPhone using PhantomPilots mobile app
     
    #4 xgaul, Apr 18, 2016
    Last edited by a moderator: Apr 18, 2016
  5. iowahill

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    I bought a drowned P2V+ bird that decided to take a swim in a pool. One motor had a bent shaft and two ESCs were bad. I upgraded to the four 2312 motors and the newer ESC's and she flies like new. Gimble and camera worked as advertised and no other problems found, Regarding rice as an absorbent, a side note. It DOES work much of the time. My brother had his cell phone fall out of his pocket and into the toilet. I had him give it another bath in distilled water, shake as much out as possible, then pack it into a bag of rice. Two days later it was working again, but the reception was crappy!
     
  6. dirkclod

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    Community Guidelines Read
     
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  7. markintheworld

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    @limepixel - I'm using rice to absorb liquid, not to repair board damage. Thank you for your input.

    I would welcome any helpful advice, if you have any to offer.
     
  8. iowahill

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    I think you're doing the right thing here, but a rinse with distilled water first would reduce the chance of water with a high or low Ph from causing corrosion or shorting of the board traces.
     
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  9. markintheworld

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    I desoldered & removed 2 obviously malfunctioning ESCs (flames &/or smoke)

    Now I can get the bird to initialize (LEDs blink: RGYRGY) and then blink yellow.

    Startup CSC gives me 5 quick red blinks then returns to yellow blink, or 2 quick yellows, repeating.

    My S1 switch was also damaged when I threw my remote aside to dive in and swim after my copter (my wife talked me out of that - water's a little chilly still. Would have been an uncomfortable ride home). I need to replace S1 to test compass calibration & failsafe function.

    Just trying to figure out my next diagnostic step....
     
    #9 markintheworld, Apr 18, 2016
    Last edited: Apr 18, 2016
  10. ARM

    ARM

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    ....
    I would replace esc's and any other part that you suspect bad pay now or pay later...... good luck keep us posted
     
  11. Mako79

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    Plug it into the PC. If the main board fires up then the PC can tell you the faults via Phantom assist software.
    The flashes you are getting can be a multitude of things - IMU, dead compass, dead GPS puck and maybe all of the above.
    You can also test your S1 switch in the phantom assist. If you are in urgent need, swap the S2 switch over. You can also do a compass dance using the DJI vision app.
     
  12. markintheworld

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    Powered up, plugged into Phantom Assistant...

    Success! for a fleeting instant....

    I received a "basic calibration error"

    I reset BTU info, re-powered main controller, and got the bird to initialize, blinking GRRR...GRRR (seeking GPS). Great!!!

    Then I attempted advanced Calibration, without success, and upon re-powering main controller received the following:
    ERROR[25]
    "IMU initialization failure, may caused by crash.[sic] Please contact dealer or DJI for repair."

    LED code: RGY...RGY...etc

    Compass dance seems successful; returns no errors.

    Does my IMU require replacement?? Is there any further diagnostic I can perform?
     
    #12 markintheworld, Apr 19, 2016
    Last edited: Apr 19, 2016
  13. markintheworld

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    Update:

    Removed Naza-M flight controller from main board to perform "desktop tap" re-calibration maneuver - I see some condensation on the inside of the case. Going to open case to see if I can dry it out...gotta find a tiny torx first...T-5 I think.
     
    #13 markintheworld, Apr 19, 2016
    Last edited: Apr 19, 2016
  14. Mako79

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    You need to do a hard tap in the opposite side of the gyro lock.
    If there is condensation - blow dry or open it up and use metho and then rice :)
     
  15. markintheworld

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    Opened up the IMU/Flight controller - boy, that's an interesting little gizmo! The bird's inner ear, its center of balance....couldn't quite discern its complete function (what actually physically senses the movement of the mass), but taking this whole copter apart has been quite an education!!!

    Cleaned up the parts with isopropyl alcohol (didn't have any methylated spirits on hand), and set in front of a fan to dry. Seems like a fair bit of oxidization from the lead block is present - I cleaned as well as I could - hope that doesn't affect function of what seems like a delicate and vital key part for stable flight.

    Powers up with normal blink pattern now! (GRRR...GRRR...etc)

    Just received replacement ESCs in the mail, will replace the 2 obviously damaged ones shortly..High hopes to get this drenched drone flying again!
     
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