Recently sold my Vision 2 Plus to a friend after I upgraded to the P3P.  I flew for yearrs with no issues.  He had a flyaway, I think due to a failed motor and ran it into a building.  He took to a local company that repairs drones.  They replaced the flight conotrooler and the bad motor, reinstalled the drivers and software, ran diagnostics successfully on the controller and the drone.  They state it will not take off.  The repair shop called me to see if I knew anything that might rexplain.  I verified that the flight controller was connected properly and that he is not in a no-fly zone.  Anyone have anything that might help?  The unit starts up fine, but won't rev up to take off.

Thanks in advance.

Could you describe the lamp sequence when the battery is in the AC and is turned on?  

Mark The Droner Posted at 2017-2-20 12:19
Could you describe the lamp sequence when the battery is in the AC and is turned on?

It is at a repair shop now.  I will be having my friend bring it back to me to figure out.  Any new thoughts welcome in the mean time.

How do they know the ESC isn't bad?  Usually seemingly bad motors are actually bad ESCs

Mark The Droner Posted at 2017-2-20 17:23
How do they know the ESC isn't bad?  Usually seemingly bad motors are actually bad ESCs

Forgive my ignorance.  I am a DJI owner of several models, but don't know what the ESC board does.  I did look it up and they are available readily.  Is the circuit board easily replaced?  I fear my friend who purchased my older drone is in a "box" and I am trying to get the unit back to me to correct.  I am an electronics engineer and capable of any work required on the internals.  Thanks Mark.

It's difficult to diagnose this because you can't answer questions that we may have.  What is the lamp sequence?  Does the bird boot up correctly?  Do any of the motors spin?  You can't tell us.

ESC is short for Electronic Speed Control and there's a board for each motor.  It's in the wing.  I just know that most of the time a failed motor is actually a failed ESC.  Yes it's easily replaced if you have $20 and can do a little soldering.  It wouldn't surprise me if there was a youtube video on it.  You're welcome.

Mark The Droner Posted at 2017-2-21 03:12
It's difficult to diagnose this because you can't answer questions that we may have.  What is the lamp sequence?  Does the bird boot up correctly?  Do any of the motors spin?  You can't tell us.

ESC is short for Electronic Speed Control and there's a board for each motor.  It's in the wing.  I just know that most of the time a failed motor is actually a failed ESC.  Yes it's easily replaced if you have $20 and can do a little soldering.  It wouldn't surprise me if there was a youtube video on it.  You're welcome.

Finally got it back from the repair shop.  The tech was obviously lost.  He did replace the flight controller and one motor and the associated ESC board.

I started from scratch and reinstalled the driver and all software for the quad and controller.  Did a full diagnostics and calibration successfully with one exception.  The X1 switch is not moving the slide on the sticks monitor.

Took the unit outside and powered it up.  Lights:  Start up:  All lights 1 long flash red with power up sound, then all light flash red-green-yellow twice.  Then rear lights flash slow yellow until GPS acquired, then blink slow green.

Powered up the controller and wi-fi extender and launched DJI Vision app.  All clear and ready for GPS take-off.

Craft does a face plant (flips forward on the ground on acceleration).  Seems it thinks it is in a different position from level, as the camera is also tilted sideways the extent of the gimbal travel and the gimbal motor is still fighting to turn it more.  If I physically tilt the craft to the right about 45 degrees, the camera levels out and the gimbal motor stops moving it.  

I did calibrate the joysticks and they all center.  All motors at idle and light increase in power seem normal and none lag.

Good description.  

Are you sure you launched aggressively enough?  I like to full thrust on launch.  I've found a light or even a medium thrust will often cause it to flip onto the ground.  

Mark The Droner Posted at 2017-2-25 10:44
Good description.  

Are you sure you launched aggressively enough?  I like to full thrust on launch.  I've found a light or even a medium thrust will often cause it to flip onto the ground.

Just did and it just caused it to slam faster and harder.

Shoot.

How about an IMU calibration?  

I have a p2 vision plus v3.0 with the same problem. I'm and compass calibration did not help

I dislike auto-correct. IMU and compass calibration did not resolve my P2 vision  plus v 3.0 face flops

To me, provided the motors are spinning correctly before launch, it sounds like a gyro that's out of whack and an IMU calibration should fix that, I would think.  

fansc0d8bd3e Posted at 2017-2-25 10:52
Just did and it just caused it to slam faster and harder.

And your certain that the motors are spinning in the correct direction after the repair? Could you happen to provide a small video of how it's behaving? There's also a chance that the guy that fixed it didn't put the ESC plugins in the proper order on the flight controller.

DJI-Jamie Posted at 2017-2-25 13:17
And your certain that the motors are spinning in the correct direction after the repair? Could you happen to provide a small video of how it's behaving? There's also a chance that the guy that fixed it didn't put the ESC plugins in the proper order on the flight controller.

That's what I am thinking.  I did an IMU calibration.  Given the camera is fighting to turn sideways to a 45 degree angle when level (if the camera attitude is related to the gyro) it makes sense.  I haven't searched extensively for proper ribbon connections, but will do.  All of the videos I have found so far do not really indicate the proper placement of the ribbon cables.  I will have time tomorrow to video and share the face plant.

fansc0d8bd3e Posted at 2017-2-25 15:44
That's what I am thinking.  I did an IMU calibration.  Given the camera is fighting to turn sideways to a 45 degree angle when level (if the camera attitude is related to the gyro) it makes sense.  I haven't searched extensively for proper ribbon connections, but will do.  All of the videos I have found so far do not really indicate the proper placement of the ribbon cables.  I will have time tomorrow to video and share the face plant.

Whenever you can would be appreciated.

DJI-Jamie Posted at 2017-2-25 16:12
Whenever you can would be appreciated.

After videoing the turn over to post here, I spent a minute checking the prop rotation and I guess you can't rely on a tech to install a motor correctly.  The guy installed the correct motor, but when I opened the drone again, I discovered he reversed the yellow and red wires on the new motor.  Result was (3) CW and (1) CCW prop.  That explains the take off problem.

I really appreciate all the input here.

I am left with one more issue to resolve and that is the gimbal motor.  Here is the link for the video and I am hoping there is a fix.  Thank You.

Good call Jamie!!!  It would never occur to me that a tech would solder the motor wires backwards.  I've never even heard of such a thing.  That is a first!

Sorry but I have no idea how to fix a motor/gimbal that's out of whack like that.  I've read posts that describe taking the gimbal apart somehow and realigning the parts correctly, but I've also read it's very hit and miss and extremely difficult bordering on impossible to get it right.  And furthermore there is no way to calibrate it to make it straight (the P3 gimbals can be calibrated, I believe).  Sorry.  Somebody else might have better advice.  You might try the phantompilots forum and seek out a guy named J Dot.  He knows a lot about P2Vs and P2V+s.  He owns at least half a dozen and fixes them all the time.  Good luck.  

For those of you who had previously asked for the video of the drone on take off doing the flip, I present for your entertainment the video I took today before opening the craft and finding the error.

fansc0d8bd3e Posted at 2017-2-26 11:42
After videoing the turn over to post here, I spent a minute checking the prop rotation and I guess you can't rely on a tech to install a motor correctly.  The guy installed the correct motor, but when I opened the drone again, I discovered he reversed the yellow and red wires on the new motor.  Result was (3) CW and (1) CCW prop.  That explains the take off problem.

I really appreciate all the input here.

When you move the camera by hand while it's turned off, does the motor seem to have a lot of friction or any restriction at all? Even though the camera is like that, can you still get a camera feed?

Mark The Droner Posted at 2017-2-26 13:03
Good call Jamie!!!  It would never occur to me that a tech would solder the motor wires backwards.  I've never even heard of such a thing.  That is a first!

Sorry but I have no idea how to fix a motor/gimbal that's out of whack like that.  I've read posts that describe taking the gimbal apart somehow and realigning the parts correctly, but I've also read it's very hit and miss and extremely difficult bordering on impossible to get it right.  And furthermore there is no way to calibrate it to make it straight (the P3 gimbals can be calibrated, I believe).  Sorry.  Somebody else might have better advice.  You might try the phantompilots forum and seek out a guy named J Dot.  He knows a lot about P2Vs and P2V+s.  He owns at least half a dozen and fixes them all the time.  Good luck.

Whenever you've just had a motor/ESC replaced, that's an error that pretty easy to do. Whenever the unit is consistently flipping in one direction, it's something you'd want to check. Repair techs are people too, so they are not infallible.

DJI-Jamie Posted at 2017-2-27 14:49
When you move the camera by hand while it's turned off, does the motor seem to have a lot of friction or any restriction at all? Even though the camera is like that, can you still get a camera feed?

Thank you very much Jamie and Mark the Droner. The Phantom Pilots site led to some videos that helped on the camera issue.  That led me to take off the back plate and circuit board on the gimbal. The center post can be held in place while the camera is physically turned to re-align. Works perfect!

Richard Schiehl Posted at 2017-2-27 20:03
Thank you very much Jamie and Mark the Droner. The Phantom Pilots site led to some videos that helped on the camera issue.  That led me to take off the back plate and circuit board on the gimbal. The center post can be held in place while the camera is physically turned to re-align. Works perfect!

Good to hear it got sorted.

DJI-Jamie Posted at 2017-2-27 23:05
Good to hear it got sorted.

Bad news.  I got everything corrected on the craft and all motors spin the right direction and all accelerate when I throttle up, but craft still flips hard forward when I try to take off.  I would think the flight controller is connected properly since all motors appear to respond to throttle.  I calibrated the sticks again and they center.  Anything else you think I might need to consider?

DJI-Jamie Posted at 2017-2-27 23:05
Good to hear it got sorted.

This this might be the problem with it still flipping over on takeoff.  Can anyone confirm this motor control cable is installed backward?  Thank You.

It appears that way:

https://www.google.com/search?q= ... Q_AUICCgD&dpr=1

Mark The Droner Posted at 2017-3-3 03:29
It appears that way:

https://www.google.com/search?q=Phantom+2+vision+plus+open&rlz=1C1AVNE_enUS623US633&espv=2&biw=1024&bih=638&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj0s6mKwbrSAhWhjVQKHeYJBSsQ_AUICCgD&dpr=1

I Thought so too.  Thanks for the link.  I turned it around and now it flips backwards instead of forward on takeoff.  Still hunting.

Richard Schiehl Posted at 2017-3-3 06:50
I Thought so too.  Thanks for the link.  I turned it around and now it flips backwards instead of forward on takeoff.  Still hunting.

When I connected the flight controller the way it should be and the unit still flipped, I found the IMU was way off.  Calibrated again and got take off.  Some drift, but I am re-calibrating everything now to correct.

Richard Schiehl Posted at 2017-3-3 06:50
I Thought so too.  Thanks for the link.  I turned it around and now it flips backwards instead of forward on takeoff.  Still hunting.

Did you already resolder the motor that was spinning in the wrong direction before reversing the M1-4 cable?