Ambient temperature too high.

Check the ambient temperature at the air inlets of the projector. Make sure that the ambient temperature does not exceed 35°C (95°F).

Blocked filter at the front side of the projector.

Clean the front filter or replace with new one. See service manual chapter "Remove and clean the front dust filter".

Malfunction air extraction system.

Check the condition of the air extraction system. The air extraction system must be capable of removing minimum 10 m³/min or 350 CFM per installed DP2K and DP4K B series digital projector.

Malfunction Fan Control board.

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