Strange behavior at higher speed

[Tobrouk]

Hi everyone!

I just got a Phantom 4 back from repair (had a crash due to a faulty battery). For some reason DJI sent me another one. Fine, except that after a few flights I'm experiencing a very strange behavior every time I get some speed. Let me try to explain what I see. You have one log file attached also.

DJI Flight Log Viewer - PhantomHelp.com

So when I go on sport mode or GPS mode without avoidance system or even RTH, when I fly faster than 30 mph the Phantom start flying in an erratic way, suddenly taking altitude and getting confused. After a few seconds I can control it back. It's very scary. On the app I get a compass error and the voice tells me that it's going ATTI.

As you can see, when analyzing the log file on phantomhelp.com, I get "speed error" "compass error" even "yaw error" and some "GPS position no match". I had another Phantom 4 for the last year and never had anything like this.

For the records, I did all the calibration (IMU and compass) even if it wasn't necessary. I flew on 3 different places (all open area without any interference). I refreshed the firmware with DJI Assistant 2 and even reseted the Phantom to it's factory default. Also I uninstalled and reinstalled the app.

So I would appreciate if you could tell me what you think... before I get to DJI support.

Cheers!

Fred

 

[Goof]

Compass error could suggest there's something wrong with the ESCs, or the DJI tech was lazy and didn't twist the motor wires tight enough before soldering them to the ESC boards. In this instance high current loads in the ESCs / field wires can spew EMF all through the bird, usually affecting the compass first, but has the capability to really confuse the bird.

Contact DJI if you're still under warranty / DJI care. It's going to need (another) rebuild, hopefully at their cost if this is a 'fresh' refurbished unit.

 

[Tobrouk]

Thanks for your input! Yes this definitively look like a faulty refurbished unit...

Here another exemple from today... I really pushed it and almost had a crash...

You have the log file and a short sequence of what it looks like in video...

Have fun!

Fred