The blade of the dowser is blocked.

Check if the blade of the shutter is not obstructed.

Disconnected wire unit of the dowser assembly.

Check if the wire unit of the dowser assembly is connected withthe Formatting Interface Board.

Damaged wire unit of the dowser assembly.

Check the wire unit of the dowser assembly for damage. Repairif possible or replace the whole dowser assembly. See service manualchapter Replacement of the dowser (shutter).

Malfunction dowser assembly.

Replace the shutter assembly. See service manual chapter Replacement of the dowser (shutter).

Malfunction Fan & Motor Control board.

Replace the Fan & Motor Control board.