Wire of the Cathode Fan is disconnected.

Remove the Light Source and Cathode fan (reference 1 image) and check the connection of the Cathode Fan (reference 3 image).

Wire of the rear fan units is disconnected from the Signal Backplane.

Remove the Light Source and Cathode fan and check if the wire unit (reference 2 image) is inserted in the Signal Backplane.

Blocked Cathode Fan

Check if the Cathode Fan is not blocked. Ensure that the Cathode Fan can turn freely (reference 1 image).

Damaged wire

Check if the wire of the Cathode Fan is not damaged. Repair if possible, otherwise replace with new one.

Cathode Fan end of life

Replace the Cathode Fan. See service manual chapter "Replacement of the Anode Fan".

Malfunction Cinema Controller

Replace the Cinema Control board. See service manual chapter "Replacement of the Cinema Controller".