double beep coming from gimbal after shell replacement

[sircking]

Hello I purchased a second hand P3A and replaced a motor and the shell, I have been having issues getting it to link to the camera sometimes connect sometimes not, it is also having issues with linking to the controller. I have done both compass and IMU calibration successfully. It lifted by itself a couple of times but I was able to bring it back was a bit scarey to see it takeoff into the blue by itself, I think return home activated but i didn't trust it to keep going by itself. anyone got any thoughts????