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Topic: Color wheel aging effects on projector lamp temperature
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Joined: Oct 27, 2007
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The amount of time our large venue projectors can be ON in the classroom has decreased over the past 5 years. One highly used projector for example will only stay on for 2 hours before shutting off due to lamp overheating. Yes we advance the filter on a regular basis, yes we check that the filter is actually advancing, and yes we have adequate ventilation for this and all the other projectors of this model.

We changed the projector with the same model we keep as spare. The spare was tested for 5 hours of continuous use without fail. However, it was tested with twin Brightness color wheels. When we swapped it with the old projector we moved the Color Reproduction color wheels into the 5 hour projector. And... now the 5 hours projector only works for 1.25 hours.

Question: Do color wheels in DLP projectors age over time? Perhaps become opaque passing less light and thus overheating the lamps? We have new color wheels in hand and plan to change them during the next classroom maintenance window.
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Joined: Mar 28, 2005
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DLP color wheels are a motor driven unit and typically are rated for a specific lifespan. There are any number of different things that could go wrong with color wheels, including polarizer degradation over time.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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Joined: Oct 27, 2007
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We were able to secure the repair manual for the PDG-DHT100L/Christie DHD-800. The advanced on-screen diagnostics give us real time DMD, Lamp and Intake temperatures and we are able to compare those to the manufacturer"s thresholds for same. Extensive testing over the past two weeks shows no overheating alarms OR any temperature even close to the maximum threshold.
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BAD NEWS: Extensive troubleshooting over the last three days in SB12 and over the past five days in Forum Control Room (prototype spare projector) yielded "no trouble found".

GOOD NEWS: Technologists are proficient at: detecting real time temperatures for Intake (Room), DMD (Digital Micro-mirror Device) and Lamps (projector bulbs). We can monitor real time RS-232 Tx/Rx data between the Crestron Control system and the Projector. We validated Crestron AV2 timings in case we need to correlate log capture with an actual failed projector event.

Back to looking at environmental factors (including rogue end users) causing the projector to shut down after anywhere from 10 minutes to 2 hours. Not just shut down, but shut down in a manner that requires technical assistance to restart the projector (hard restart at the power switch).

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Classroom Projector

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