Unit is shutting down due to bulb overheat - Optoma EP739 Multimedia Projector

My EP739 never got to the point where it actually shutdown due to overheating, but the root-cause may be the same. First thing you must do is clean out any dust and debris that may be restricting airflow. If that doesn't help then read-on...
My Optoma EP739 started exhibiting color-banding and strong color shift after years of great service. After trying other suggestions that didn't work, here is the FIX for my unit. I have not seen this posted anywhere else.

Problem: After 10-20 minutes of use, color-banding and then a strong shift to purple/green with almost no red. If the unit is turned off for 5-10 minutes to cool and then powered-up again the problem goes away, only to come back in another 10-20 minutes. Enabling the "High Altitude" setting in the Setup Menu helped for a while (a week or two) since it forces the main cooling fan run at high speed always, but then the problem re-appeared.


Reason: Overheating. The electronics are overheating. Like several people have suggested: First step: Open the unit up and blow-out/vacuum all of the accumulated dust. Assure BOTH fans (there is a small drum blower directly cooling the lamp and a larger regular fan that circulates air through the entire unit) are operating and clear of debris.

Once you have done that, then look for the REAL issue. With the front panel (i.e.the panel with the hole for the lens) removed and looking into the projector from the front examine the metal heat shield on the right side above the lamp. In my unit, because of years of service and heat, the aluminum lamp housing had deformed slightly, tilting this sheet metal heat shield directly INTO the air stream from the fan. This restricts the airflow enough to reduce cooling capacity. This metal shield should be high enough above the lamp to be TOUCHING the plastic case. If it is bent down and is halfway into the air stream then it restricting the exhaust airflow, causing the overheating.

Fix: Bend the heat shield back up so that it is not in the exhaust airflow. It must be ABOVE the airflow, protecting the plastic case from the heat of the lamp. This simple remedy fixed the issue for me. My projector has been running 2-3 hours a day for 10 days now with no banding issues at all. That's it. Simple fix.