Loss of signal after crash. P3 survived but ...

Nanomien · Oct 3, 2015

Im always careful while flying, but today it happened. I crashed my Phantom 3 Pro in a tree. Luckily it was on very low altitude (3 meters/9 feet). It went upside down on the way down and crashed with propellers down and the legs up. The camera flew off and two propellers was chipped. But the Phantom it self survived. Thank god!
I changed the propellers to see if the P3 still worked. Fired it up and got GPS signal and no error messages. Checked the IMU calibration and everything seemed normal. Of course I didn't have any video stream since the camera was broken.

With the story told, here is the issue: The signal fall out from time to time. The display changes between green and red (no signal). The strange thing is that I could start the motors with "no signal" on the display.
I went out in a large field and took off on low altitude for some testing. It flew like a god! Didn't notice any difference in behaviours after the crash. And while flying the signal loss didn't happen. Strange.
My question is: Could this signal loss be triggered because the P3 doesnt find the camera? If so, my day will be saved. New camera is'nt that hard to get!
Anyone knows?

Cheers.

Edit: The legs with the antenna cables seems unharmed. And the Phantom crashed with the legs up. And it hit the tree in low speed.

flying treasure · Oct 3, 2015

I had the exact same thing happen about four days ago and the crash seems the same. Tree, 10 feet, camera off of phantom, propellers grass stained. I tried it without camera and it was telling me the same thing. Though my camera was not damaged. So the next day I hooked the camera back up and the signal was back and everything was fine. So for me that's what I think it was. The only thing that seems a little different is that it doesn't hold its position as well. When I originally got it it would not move in the air at all. After the crash it wanders around in place about a foots length back and forth trying to hold position. I think maybe my motors might have got bent just slightly. Hope yours works out!

Nanomien · Oct 3, 2015

Thanks for reply, flying treasure. I think this confirmes what I think

I will order a new camera and hopefully it will be okay, like yours. Mine phantom seems stable after the crash. But im afraid the engine got quite a punch since two of the propellers hit the tree (they got chipped off, and I heard a loud smack). But still, it flies stable.

swoopair · Oct 4, 2015

flying treasure said:
I had the exact same thing happen about four days ago and the crash seems the same. Tree, 10 feet, camera off of phantom, propellers grass stained. I tried it without camera and it was telling me the same thing. Though my camera was not damaged. So the next day I hooked the camera back up and the signal was back and everything was fine. So for me that's what I think it was. The only thing that seems a little different is that it doesn't hold its position as well. When I originally got it it would not move in the air at all. After the crash it wanders around in place about a foots length back and forth trying to hold position. I think maybe my motors might have got bent just slightly. Hope yours works out!

I'd guess that your stability issues mean that your compass might be failing. Fortunately, it's a very cheap replacement part and easy to install.

flying treasure · Oct 4, 2015

Really? Thanks swoopair. I'm still rather new to this so I wouldn't have guessed that. I calibrate it fine and it doesn't seem to lose signal when I'm flying. Should it be more stable even in low/medium winds just hovering?

Nanomien · Oct 4, 2015

Wow. Glad to hear that for your case, Flying treasure!
My phantom moves arond a little bit when hovering im medium wind. I think it moves maybe 1 to 2 inches left and right/back and forth. Not much.
But if im hovering above high grass, and the propellers make the grass blow around it's even more unstable. I think it's because the sonar get confused by the grass that moves around.

Nanomien · Oct 7, 2015

For the record: my camera arrived today. I mounted it and everything worked well! No problems at all. Lucky me. The camera is very easy to mount.

flying treasure · Oct 7, 2015

I calibrated the IMU again a flew on a non windy day and it's way more stable now!

Djud · Nov 11, 2015

I had similar situation with P3P. After light crash yesterday one of the legs bent and antenna (or what ever is 5cm long plastic part with one wire going in) pop out. It is the rear right leg with the compass underneath (I think) where other 4 wires goes through. Motors and props are not affected. There is a few little scratches on gimbal and camera but stayed in place. But there is app red indicator - no signal. So transmitter and Phantom communicate but without seeing video. After setting that antenna in place, I got video.

Everything looked alright so I tried it in the field. The P3P fly completely as before with no any problem. And the video is there. But then I landed (in hand), switch it off and on, and now there is no video signal again. I tried to fly that way. No problem at all (I haven't fly longer than 30m). I recorded the flight even I haven't seen any video on the screen. The clip looks perfectly fine.
I switch it off and on again (also remote and app) and change the usb cable, - now image appeared. Switch it off and on, no video. Few more times, no video signal again. All the time I can record or take pictures with no problem. Problem is obviously in sending video signal from Phantom to the screen, but not with the controlling signal since it always works fine.
All the cables look fine and in place. I tried to press flat ones slightly but without changes. I disconnected and connected other gimbal small white wires, no help. But there must be some triggering issue I can't figure out.

Does any body knows what part of antennas are intended for sending video signal or it is the same for both video and aircraft control?
Is it possible that problem is in gimbal/camera, antennas, cables or some other transmitting part of the flying device?

Nanomien · Nov 14, 2015

It's hard to say the reason, but I would try to by a new pair of legs for your phantom. If they are bent the cables inside could be damaged. Since the legs are the antennas that communicate between your RC and phantom, that could explain your signal loss.

Djud · Nov 15, 2015

That sounds logical. Thanks for your answer. I hope that is the cause and I will solve it in the next days.

Nanomien · Nov 15, 2015

Let me now how it goes! And remember to do a IMU calibration before you fly. Always nice to do that after a crash.

Djud · Feb 5, 2016

I sent it to service. It turns out that the reason is faulty OFDM module. Probably most expensive fault for crash from 3m altitude. I tried do claim the warranty but the DJI rejected it.