P4 Take off Problem - No errors Detectable

[Steve Kurlin]

Hi All,

My P4 starts up normally. I have the latest firmware on all devices.

When I try to take off the props all rotate correctly and come up to speed. It then flips backward and of course fails to take off.

I have performed the following :-

1. I have calibrated the Vision Sensors using DJI Assistant 2 (Latest Version) - No Errors and camera images look clear and good
2. Calibrated IMU. - No errors
3. Calibrated Compasses - No errors
4. I pull both sticks on the remote to run all motors at idle. - No errors and props seem to vary speed correctly.
5. There are no warnings while turning all devices on. IMU warms up and all statuses are clean.
6. I have performed a refresh of all firmware - No errors and runs clean every time
7. I have restored factory defaults.
8. Checked that the Black Props are on the black motors and the silver props on the white motors.
9. Checked all props are secure and no obstructions.
10. Auto Calibrated Gimbal -No errors and Gimbal seems correct
11. Remote Calibrated - All Sticks look good through all motions and no errors.

I do get a propeller error but only after trying to take when the props hit the ground. (This would be expected)

Does Anyone have any suggestions as to what maybe the issue or how I can diagnose this?

Steve

 

[dorbot]

Did you nail one side of the aircraft to the ground? Dynamic rollover?
Kidding!

Sounds like the controller for two of the motors might be faulty. Has it ever flown?

 

[Steve Kurlin]

Did you nail one side of the aircraft to the ground? Dynamic rollover?
Kidding!

Sounds like the controller for two of the motors might be faulty. Has it ever flown?

It seems to rollover to the rear right. I guess it could me a motor or ESC Board for that motor but it seems odd that all motors run up and test ok with the idle test and I get no ESC errors. I will replace the motor and ESC board and see what gives. Thanks for your time.

 

[alokbhargava]

Are you sure the directions of the motors when they rotate are correct. Adjacent motors should rotate in reverse direction. This may happen if you ever replaced the motor connections.

 

[Droneted]

I had this same thing happen. I replaced the motor and solved the problem

 

[Steve Kurlin]

Thanks for the responses guys. I have checked the rotation as suggested and they do seem to be ok. I compared them with another phantom 4 to make sure they are spinning in the right direction. I think there is nothing else to do but replace the motor and if that does not fix it replace the associated ESC board. I still think it strange that none of the diagnostics or checks reveal anything. I will update this thread after the replacements.

 

[Droneted]

I had no error reports on mine but noticed it flipped the same way every time. I had to make my best guess as to which motor was bad. Really strange

 

[Steve Kurlin]

I finally found the problem. I found the black cable on one motor to be broken. It looked like it was wedged between the upper and lower shell at some point. The wire was badly crushed but it had enough of it to still run up the motor but I am assuming that when the motor was under load the wire either vibrated enough to break connection momentarily or the connection could not carry the current required. I patched it up and the drone is now back in the air.
Thank you for your replies it provided me with the right direction to diagnose the problem

 

[dorbot]

Cool.