It seems that lately my artificial horizon (AH) tumbles according to the very random and fluctuating pitch roll and yaw values visible under the status display in mission planner. Using 2.76 and about at my wits end here. I have tried reflashing APM, reflashing both 3dr radios, disconnecting airpseed sensor, setting GPS AHRS gain to 0 (it is now back at its default of 1), and am out of options.
The system runs perfectly fine under a USB connection to the computer. AH is stable and all other indications appear fine. It just seems like pitch roll and yaw goes haywire when the 3DR radios are connected. I am not able to do a level or a accelerometer calibration while using the radios. I get the message: “ac2 2.0.37+ is required”. I have no idea what this signifies.
I am able to switch modes using the radio, and connect fine every time. I am also able to execute commands, such as a Preflight_Calibration via the radio. Airspeed indications are also normal over the radio. It seems like there is only an issue with the gyro portion of the connection.
Does anyone have any insight into possible troubleshooting actions that I could take at this point?
Attached is a youtube video of what I am experiencing:
[youtube]http://www.youtube.com/watch?v=nDtBnEUJtdg[/youtube]
If it were the 3.3v regulator wouldnt the problem appear over USB as well? This issue only arises when connecting via the telemetry radios. When I revert back to USB everything is fine.
Well, now it appears that the unit is tumbling under USB as well. It will not accel calibrate under USB nor will it calibrate level. I am beginning to think that the unit is simply defective.
You were absolutely correct. By testing volts across pins 1 and 4 of the I2C port I was able to read 5V instead of 3.3 indicating that the 3.3V regulator was indeed blown. How this came about I have no idea, it seemed random, and just started doing this one day. Thanks for the great tip. I’ll link that video here in case anyone else has issues with the artificial horizon going nuts. In this case, I thought it was just over the 3DR radio, but it turned out to be under USB as well.