Fortunately issues with Sony’s cameras are rare, but should you encounter a serious issue with your FX9 it will more often than not display an error code on the LCD screen. This will typically start with an E12, E91 or E95 prefix followed by 3 more numbers or letters.
E12 errors are normally related to the ND filter or the mechanism that moves the ND filter in and out of place (there is a screw accessible from the underside of the camera body that can be used in an emergency to wind the ND filter – DO NOT USE THIS – except in a get me out of jail at all costs situation).
E91 errors are generally related to the cameras main DPR394 board and in particular the main video and audio Input/output and coded chip. Or communications between the main board and other sub units within the camera.
E95 errors are generally related to the cameras CPU/DSP and PCIe bus (again on the main DPR394 board).
Sometimes a non Sony lens or Lens adapter can cause the camera to throw up an error code, so one thing to try if you see an error code is to remove the lens or lens adapter to see if the error goes away. 3rd party batteries can also sometimes lead to an error code.
Unfortunately other than lens/lens adapter or battery issues an error code will typically mean the camera needs ro be looked at by Sony or an authorised service center, but there are a few error codes that you might be able to deal with yourself:
E91:1D0 : This error is a communication error between the main board and the GPS unit in the cameras handle. Check that the handle is correctly attached and not lose. If you remove the handle you will get this error unless you turn off the GPS in the menu.
E91:360, E91:367, E91:36C are caused by faults in the XDCA-FX9, so if you have an XDCA-FX9 on the camera, removing the XDCA will normally clear these error – but your XDCA will need to be repaired.