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Equalizing CRT Phosphor Wear Patterns

Re-Use or Extend the Useful Life of CRT Projector Tubes

Proj A_green tube mod 533

Phosphor Wear Pattern on Face of One of Two Green CRT Projector Tubes.
The Effect of This Wear Was Reduced Using the Procedure Outlined Here

Note: this article is several years old but may still be of interest to some home theater enthusiasts.

CRT (cathode ray tube) projectors may be a dying technology, but they are not dead yet. Despite their size and weight compared with digital projectors, CRT projectors have some advantages that an enthusiastic subculture of home-theater aficionados cannot abandon, at least until something truly better comes along. CRTs can produce the deepest and most uniform black levels, and tube life far exceeds the lamp life of a digital. CRT projectors, despite their complexity, are highly repairable compared to a typical digital projector where even the replacement of the lamp may be cause to abandon the whole unit and buy another.

In a CRT projector three separate images produced on the faces of red, green, and blue tubes are converged and projected via separate lenses onto a screen to create a full color image. The light is actually produced by an electron beam striking a phosphor coating on the faces of the tubes.… Read the rest

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