DJI Mavic Pro having issue with gimbal

DJI mavic pro having issue with gimbal. It moves during power on but after that I can’t move it via transmitter. There is no video feed and inside Go4 app it shows gimbal disconnected.

Went to a repair shop and was told that it’s motherboard issue. Wasn’t convince and believe it should be gimbal card and video cable issue.

Anyone experience this issue before?