TrueView systems can be powered from internal battery power or externally powered from drone platforms using the appropriate power connector. Occasionally, there may be an issue where a TrueView system may not be able to be powered from the top power connector on an M300 platform.
The TrueView system may power on if the user presses down on the power connector while it is plugged into a drone that is powered on. Then the TrueView system will power back off if pressure is released.
Probable Resolution #1:
On the power cable, there is an O-ring on the connector. Remove this, then plug it back in and attempt to power the system on.
Probable Resolution #2
On certain M300 platforms, the connector may not sit flush due to the connector port on the drone sinking down into the body, preventing a good power connection.
In this case there may be an issue with the power connector on your drone and will need to contact DJI support to repair the sunken connector.