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Question

Difficulty: MediumVideo, Display, and Projector Issues

A field technician is troubleshooting a DLP (Digital Light Processing) projector in an executive conference room. Presenters report that projected presentations frequently display rapidly flickering colored bands and severe color distortion. The technician accesses the projector's built-in On-Screen Display (OSD) menu and notes that the menu text and graphics exhibit the exact same color shifting and flickering. Which of the following components is most likely failing?

  1. The projector color wheel assemblyAnswer
  2. B
    The high-voltage backlight inverter board
  3. C
    The video source signal cable bandwidth
  4. D
    The host computer graphics processing unit driver

Answer

The projector color wheel assembly
The correct answer identifies the projector color wheel assembly as the failing component. Single-chip DLP projectors use a spinning color wheel to place color filters in front of the light source in rapid synchronization with the Digital Micromirror Device (DMD). If the wheel motor fails or its speed sensor becomes desynchronized, severe color distortion or flickering color bands occur. Because the internal On-Screen Display (OSD) menu also shows the defect, the problem is conclusively internal to the projector hardware.

Step-by-Step Solution

1
Analyze the reported visual symptoms
Identify that rapid flickering colored bands and color shifts indicate a failure in the optical color generation system.
DLP projectors rely on a rapidly spinning wheel with red, green, and blue filters to synthesize full-color images sequentially.
2
Isolate the issue between external input and internal hardware
Observe that the built-in On-Screen Display (OSD) menu displays the exact same visual defect.
Because internal OSD menus bypass external cabling, ports, and host computer display drivers, any defect present on the OSD proves an internal projector hardware fault.
3
Identify the failing physical hardware component
Confirm the color wheel mechanical motor or sensor timing has failed.
When the DLP color wheel motor slows down or loses synchronization with the digital micromirror device (DMD), image colors break down into flashing bands.

Key Concept

DLP Projector Hardware Diagnostics
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Topics

Video, Display, and Projector Issues

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