All magnetometers 0

Hey, I problem with my Quad.
Every time I try to arm the message is “Compass not healthy”.
All m values under status are zero.

I have a Pixhawk and a u-Blox Neo M8N.
With Copter 3.6.0 I was able to fly, although I had to deactivate the external one, since I couldn’t calibrate it.

Yesterday I upgraded to 3.6.3 and showed a friend the setup process because he was interested. But now I can’t arm and most of the times I can’t achieve a calibration of the compass. Sometimes it works but most of the time it doesn’t.

To me this sounds like a hardware failure. Do you have any ideas how I can solve this problem or do I just have to buy a new GPS-Unit and Pixhawk.

Thanks in advance.

Okay, now I’m really confused.
I bought a new Pixhawk, still all values remain zero and I have the Prearm message Compass not healthy. I also tried switching the two lines from the external compass, still no values…

Any ideas?

Thank you

Edit: Could it be that the external compass fries the I2C bus somehow? Because I connected the external compass to an old APM Quad and now also the APM only gives prearm: Compass not healthy. And it worked fine before, I’ve checked it.

So invested more time (and money, so far 3 Pixhawks and 1 APM) into the problem.
I’ve set up a completely new Pixhawk, compass worked fine until I plugged the battery in for the first time.
But I’ve checked the power input to the Pixhawk and it delivers exactly 5 volts…
So I don’t see where the problem could be…
Any ideas?

Thank you

I have an update (Sorry for possible double-post):
I’ve stumbled across this post: https://diydrones.com/forum/topics/pixhawk-i2c-not-working
I thought I’d give it a try and to my surprise ALL controllers are working!
So the good news: I didn’t break anything.
And the bad: Why does the compass stop working once I plug in the battery and how can I avoid that, so that I can fly… Secondly: What do I do with two spare Pixhawks? but I’m pretty sure I’ll find a solution to that problem :wink:

I investigated a bit deeper into the issue and it seems to be the compass calibration.
Before the calibration, it shows values and those change.
After the calibration and before I reboot the Pixhawk, the values are frozen.
Then, after the reboot, all values are zero until I reset all values to standard.
So this seems like a software issue to me, should I create an issue on github?