If it flips on take off then the m1-m4 cables have been installed upside down.
Mako,
You are correct. I discovered this last week. Thanks to you and so many others on this and the DJI forum. I sold this craft to a friend after I upgraded and he crashed it and took to a business that advertised drone repair. The rest began the nightmare. I was an electronics engineer in the early 80's, so asked him to bring to me after the major fail of the repair facility.
A chronology of the ordeal:
1. Ben experienced a runway flight resulting in an allision with a building. The flight
controller harness had been pulled loose thus. Ben re‐connected the flight
controller and the craft would not respond to commands.
2. Ben brought the unit to ########### in Pensacola, Florida for repair.
########### determined the flight controller module, the forward
starboard motor and the associated ESC board needed replacement.
3. The tech replaced the parts and then reported the unit checked out positive on
all diagnostics and started up normally, but would not take off.
4. I communicated with the tech on several occasions to offer suggestions including
reinstalling the craft and remote control software and calibrating everything.
That was reportedly performed with no change in status. The tech called me and
let me listen to the craft as he tried to take off. There was a slight increase in
RPM, but not enough to take off.
5. Part of what I communicated to the tech was I had used the DJI Phantom Vision 2
Assistant software to reverse the functions of the left and right joysticks. When I
later received the drone from Ben it was apparent the tech was using the wrong
joystick to take off.
6. I received the drone from Ben on February 24, 2017 immediately after he picked
it up from ############### (still reportedly not taking off due to limited motor
speed).
7. Several screws were missing from the case of the craft (one later found INSIDE
the unit).
8. When I took the drone out of its case, I noticed a rattling from inside the unit. I
removed the cover and discovered several solder pellets in the arm in which the
motor was replaced. I removed what I could, but there was still at least one
trapped under the ESC board. The board would need to be removed to retrieve
the pellet, but the wires soldered into place on the board by the tech blocked the
access to one of the mounting screws.
9. The (5) solder locations performed by the tech were poor and resulted in heat
damage to the ESC board and the insulation on several conductors was found to
be burned off. The wire bundles for the repaired motor arm were not tied
together as recommended by DJI.
10. That evening I powered the craft up and attempted to take off (using the correct
joystick). The motors gained their normal speed without issue until the craft
started to take off and then flipped itself tail over nose onto the ground.
11. I dissembled the craft again and found the motor that had been replaced was
wired incorrectly, resulting in the motor turning clockwise instead of counter
clockwise. This resulted in (3) clockwise props and (1) counter clockwise prop,
creating the imbalance that forced the craft over on takeoff.
12. After rewiring the motor, the craft still flipped over on takeoff. I dissembled the
craft again to check the replaced flight controller and found the motor harness
had been connected backward, resulting in the craft trying to compensate on the
wrong motors.
13. The camera issue was not addressed by the tech. The impact from the allision
resulted in damage to the gimbal motor drive shaft to camera interface. I
opened the gimbal to access the drive and shifted the shaft to level the camera
and correct the problem.
and
14. After my corrections to the faulty repair and after performing further repairs, the
craft is flying again.
