Hi All,
This is my first post. I think this doesn't violate the forum rules as this doesn't count as a modification, but rather a repair.


I am new to the drone world and was recently given a Mavic Air 1 destined for the rubbish bin. Around two years ago the drone took a dip in fresh water for a few minutes due to pilot error (flying too close to a waterfall). The mavic was retrieved and battery removed before being left out to dry completely. The previous owner was unable to get the drone to fly afterwards. Fast forward two years and the mavic is now in my possesion.

Initial tests indicated that the MA is 99% functional apart from a 'Battery Signal Error' that prevents takeoff; the camera, flight sensors, IMU, GPS, etc are all functional and calibrate without issues or errors. Rotors spin smoothly (with expected cogging) and move during the start up process. The batteries charge and 'function' without errors, however I have retired one as it is showing very slight cell swelling/off-gassing.

I disassembled the MA to inspect for damages expecting the worst but found no visible corrision but did see mineral deposits/white dust on the EMI covers on the main/CPU PCB. There is slight corrosion/discolouring on a few contacts on the main camera cable connector however the camera 100% functional. I cleaned the boards and connections with PCB/electronics cleaning spray but the 'battery signal error' is still present (not that I expected things to be that easy).

I checked continuity on the I2C/SMB lines from the battery connector through to the CPU board and can not see any obvious shorts or open circuits. I can't trace up to the CPU as it is difficult to do so. The components under the EMI shields appear to okay based on a visual inspection, no contaimination or corrosion is present. I would like to check the bus voltages while the drone is powered as this may indicate if a TVS diode or such has failed but don't want to risk bricking the MA completely with a slip of the probes.


I have ordered a used ESC board from a scrapped functional MA to replace the suspect board; failing that I will attempt to replace the main board.

My questions are:

• Are the ESC and mainboard 'married' via serial number or calibration parameters? If yes, what is the process to follow after replacing the ESC PCB?
• What is the recommended method of removing the strain-relief/vibration-damping silicone around the soldered connections for the motors and LEDs?
• Is there any way to bypass the 'battery signal error' to check the motor operation under full power. I'm not expecting full flight capabilities for obvious reasons.
  

Should the replacement(s) not resolve the issue, I would like to use the MA as a helmet mounted action camera.


Thank you

Hello there ChrisE99. Thank you for reaching out and for giving out these information. Since we are having this issue with your DJI Mavic Air, I would recommend for you to contact our DJI support team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We will do our best to help and will give out the best resolution for this issue. Just a friendly reminder that  DJI do not recommend doing a DIY in fixing your DJI drone to avoid further damaging the unit Again, I am sorry for the trouble and thank you.