Recovering from water damage, need help with testing

[dougvg]

Hi all,

This is my first post. I recently dunked my Phantom in the river, where it stayed for 24 or hours before I found it. I took it all apart, washed it out, dried it for two days in front of a heater, then in a bag with silica gel. I hooked it up to the computer, and everything checks OK. I recalibrated the controller, etc., and all was nominal. I then took it outside and let it initialize. It acquired 6 satellites in the normal time. I started it up (my wife held it above her head, so it wouldn't take off) and revved the motors -- still all OK. Then I spun the motors up to about 80% and left them there for 10 seconds. This is when the trouble began. The motors stayed at that speed and could only be brought down by turning them off. Not good, I thought. So I brought it in, dried it another day, unplugged and cleaned all contacts on the main controller, and tried it again without props inside. The same thing happens. When I increase the speed momentarily, even to 100%, and let the throttle center, the motors come back to idle, but after I keep the speed up for 3 seconds or so, they stay up, and fail to return to idle.

My working theory is that the Phantom is attempting to stay in the air after what it thinks is a takeoff, and the motors don't come back down because it's trying to stay aloft. Is there any validity in that theory? How could I troubleshoot this behavior?

Thanks for any help!

 

[amrflyingdude]

Hi all,

This is my first post. I recently dunked my Phantom in the river, where it stayed for 24 or hours before I found it. I took it all apart, washed it out, dried it for two days in front of a heater, then in a bag with silica gel. I hooked it up to the computer, and everything checks OK. I recalibrated the controller, etc., and all was nominal. I then took it outside and let it initialize. It acquired 6 satellites in the normal time. I started it up (my wife held it above her head, so it wouldn't take off) and revved the motors -- still all OK. Then I spun the motors up to about 80% and left them there for 10 seconds. This is when the trouble began. The motors stayed at that speed and could only be brought down by turning them off. Not good, I thought. So I brought it in, dried it another day, unplugged and cleaned all contacts on the main controller, and tried it again without props inside. The same thing happens. When I increase the speed momentarily, even to 100%, and let the throttle center, the motors come back to idle, but after I keep the speed up for 3 seconds or so, they stay up, and fail to return to idle.

My working theory is that the Phantom is attempting to stay in the air after what it thinks is a takeoff, and the motors don't come back down because it's trying to stay aloft. Is there any validity in that theory? How could I troubleshoot this behavior?

Thanks for any help!

Do the same but in manual mode, this way you will now for sure if this is the NAZA revving up the motors or not. I think everything is fine (based on your description) but I give Kudos to you for checking thoroughly.

Good job!

 

[dougvg]

In manual mode, it seems to react properly, assuming that in manual the motors don't idle when the throttle lever is at center, but must be brought down to idle manually. The throttle lever in manual will run the motors at about 50% in the middle. I just tried it in GPS and ATTI and got the bad results - motors racing out of control and randomly wants to go right and left randomly, inappropriate response to lever positions, failure to idle at throttle centered.etc. It's if it's getting bad signals from the GPS unit or the Naza Controller is giving random signals to the motors. Again, this on;y happens when the motors have been spooled up for several seconds - as they would in a takeoff.

 

[tiagobaracho]

You must have many electrolysis point on many boards... you have to remove it.. did you clean the solders that were not shining ? did you open the Naza case to see the board situation ?

 

[tiagobaracho]

i would for sure also change the bearings.... i will rust ... bearings are very sensitive to any water.. .and the bearing on those motors are not sealed, so , for sure water came in...

 

[EMCSQUAR]

In manual mode, it seems to react properly, assuming that in manual the motors don't idle when the throttle lever is at center, but must be brought down to idle manually. The throttle lever in manual will run the motors at about 50% in the middle. I just tried it in GPS and ATTI and got the bad results - motors racing out of control and randomly wants to go right and left randomly, inappropriate response to lever positions, failure to idle at throttle centered.etc. It's if it's getting bad signals from the GPS unit or the Naza Controller is giving random signals to the motors. Again, this on;y happens when the motors have been spooled up for several seconds - as they would in a takeoff.

Try this - Go to assistant ->basic -> RC and calibrate sticks. Then do an advanced IMU calibration

 

[dougvg]

Tried the advanced IMU calibration - no dice. I now have changed the NAZA-M V1 to a NAZA-M V2, and still have the same symptoms. This is driving me nuts! Why would this happen only after 3 seconds of high power? What sort of timer is there in this system that takes control after 3 seconds?

 

[FSJ Guy]

My working theory is that the Phantom is attempting to stay in the air after what it thinks is a takeoff, and the motors don't come back down because it's trying to stay aloft. Is there any validity in that theory? How could I troubleshoot this behavior?

Thanks for any help!

I think that is what is happening. Think about it: Once it's in the air, even with the sticks at neutral, the props will be spinning faster just to keep it in the air and not falling.

I think you're just going to have to bit the bullet and do a test flight.

In a large open area.

 

[dougvg]

Well, I bit down hard on the bullet and tried a test flight - it worked perfectly! The problem I was experiencing, in Microsoft terms, was a feature, not a problem at all! Apparently if you start the motors without props and spin them up, the craft thinks it's in the air and tries to maintain a hover. Nice to know!

 

[FSJ Guy]

Glad to hear it's working again!

Now stay out of the water for a while!!! :- p

 

[Vertical#drifter]

Same EXACT thing happened to me today. I was returning back over the ocean, when it just promptly descended with no warning. I tried to increase climb, but there was no response. My only saving grace was a beeline to the shore....and splash. Only a few feet in, but retrieved it after 5 minutes. It was still operating...I hosed it with fresh water (I'm at a resort in Panama)...get back home in a few days...there's sand in the engines. It's dried, but makes a funny noise when I turn it on...I'm hosed
Any suggestions would be great...first time on this site. Also, FYI, the lighter side of all this...it's gonna make for a bitching video
Cheers,

 

[rfernandez]

Kudos, it could have been a $1200.00 bath.. you are lucky!!

 

[lbozka]

Re: Water Damage Repair Shop?

My Phantom 2 Vision is water-damaged (freshwater). Called DJI Los Angeles. Hold time was over two hours. Finally spoke to a guy who told me DJI will not even touch water-damaged quads. Anyone know of a repair shop that works on water-damaged Phantom 2 Vision copters? Camera is almost certainly toast, but I would be thrilled if it could be rendered flight-capable w/o camera for practice purposes.