Wire unit (reference 1 image) of the Cold Mirror fan (reference 2 image) disconnected.

Remove the left cover of the projector and check the connection of the wire unit of the fan below the Cold Mirror. Simultaneous check if the wire unit (reference 3 image) of the SPG fan (reference 4 image) is not disconnected as well.

Wire unit of the fan units (reference 5 image) disconnected from the Power Backplane.

Remove the front cover and front dust filter from the projector and check if the wire unit (reference 5 image) is inserted in the Signal Backplane.

Blocked fan (reference 2 image).

Unblock the fan. Ensure that the fan can turn freely.

Damaged wire unit.

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

Malfunction Fan Control board.

Replace the Fan Control board. See service manual chapter "Replacement of a Card Cage board".

Fan end of life.

Replace the fan. See service manual chapter "Replacement of the SPG/Cold Mirror fan".