At a site, the OSN6800 fan reports the FAN_FAULT alarm. During the onsite replacement, the fan unit (fan box) cannot be removed. As a result, the fan unit cannot be replaced and cannot be further processed onsite. Therefore, you are advised to replace the subrack.
The screws are completely removed, but the fan tray assembly cannot be removed.
You have applied for a spare subrack. In the case of the worst case, you need to replace the subrack. After the subrack arrives at the site, pull out the fan tray assembly again, and then pry the fan tray out. The problem is found. The protruding screw of the fan tray assembly is severely scratched, as shown in the following figure.
External view of the cabinet
This screw is used to fix the left and mounting ears of the stator. However, the screw specifications are incorrect and too long. As a result, the screw is protruded after the screw is tightened, and the middle part (shown in the yellow circle) is in the fan tray assembly. As a result, the fan tray assembly cannot be removed.
To solve this problem, you need to replace the screws with a proper length. The left side of the cabinet is installed side by side and there is no operation space. Therefore, you need to remove the four mounting ears and columns and pull out the subrack to replace the screws. The four mounting ears and subracks of the site are securely installed and have guide rails (guide rails) for bearing support. No suitable short screws can be found onsite. Remove the protruding screws from the mounting ears at the lower left corner and insert the fan box. The fault is rectified.