CF 2.0 suddenly out of control while flying

[grilly]

Hello,

Our CF2 flies normally for a while and suddenly it spins out of control and crashes. Connection is still active. After putting it on level ground the horizon is gravely incorrect and does not recover. In addition, when moving the CF2 by hand there seems to be a scaling issue, e.g. 45 degrees of motion show up as much less in telemetry. "Turning it off an on again" fixes this misalignment, until the error occurs again.

- We have a second CF2, which is behaving as expected without any crashes using the same Crazyradio.
- All selft-tests pass on power up.
- Battery is well charged.
- A firmware update did not fix this issue.
- Error also occurs when flying/manouvering at half thrust using our test rig (a string hanging from the ceiling)

It seems like a hardware issue. My guess is, there is something wrong with the gyro, but it's just a guess.

How can I check if something is broken? Any ideas how to fix this error?

Thanks in advance,
Lukas

[chad]

Maybe you could try flashing the IMU test firmware attached to this post and see if the results pass...

[grilly]

Thanks. Looks like the gyro failed:

SYS: ----------------------------
SYS: Crazyflie is up and running!
SYS: Build 6+:29624e7f6e3b (2014.12.0) MODIFIED
SYS: I am 0x313238323133471529001A and I have 1024KB of flash!
IMU: MPU9250 I2C connection [OK].
IMU: AK8963 I2C connection [OK].
IMU: LPS25H I2C connection [OK].
EXPBRD: Found 0 memories.
EEPROM: I2C connection [OK].
MPU6500: Self test gyro X [FAIL]. low: -14.0, high: 14.0, measured: 25.95
OW: Found 0.

Is there something I can do about it?

[tobias]

Do you have any access to a hot-air repair/reflow station? There might be a cracked solder connection of the MPU9250 that is causing it. If you hold down the MPU9250 when running the self test FW does it make any difference. The MPU9250 is U9 in this drawing.

[grilly]

Yes, we have one of those, but I'm not comfortable using it as long as we have warranty. We ended up shipping it back to China.
Thanks for your help.

To be closed.