Panasonic PT-AE500U Pink "Splotches"

Discussion in 'Displays' started by Paul Pratt, Aug 8, 2005.

  1. Paul Pratt

    Paul Pratt Stunt Coordinator

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    Hey everyone,
    I've had a Panasonic PT-AE500U projector for a little over a year and I love it, it's amazing.
    Now I'm getting pink/ purple splotches on the screen when I watch a film.
    I've looked at the screen first to eliminate the obvious, but it wasn't until i took off the source and let the projector run in it's blue screen that i discovered it was the projector. I held up a sheet of paper to the lens and the splothces where everywhere, not just in the one spot i had seen them while watching tv.
    I'm assumed this was dust or maybe grease on the lens so I got a lens treatment and tissues from the theater I work nights at, and I cleaned off the lense really well.
    It's didn't clean it up. So it makes me think the dust is inside the lens.
    How do I get this fixed? It's very frustrating and takes me out of my films.
    If anyone has any advice it would really be appreciated.

    Thanks.
     
  2. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Dust blobs ... open up the light bulb chamber ... remove bulb ... take compressed can of air and blow ....

    This might help a bit.

    Also be ready to accept that the unit might be developing some discoloration if more than 1000 hours on the unit.

    Regards
     
  3. Paul Pratt

    Paul Pratt Stunt Coordinator

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    Thanks for the quick response.
    Now on the discoloration i have some questions:
    What exactly happens with discoloration. What causes it, where does it happen, can it be prevented, or fixed.
    The unit is just slightly over 1000 hours.
    Is there a projector that doesn't do that? Image quaility is my number one priority.
     
  4. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Discoloration can usually come as a result of the blue polarizer plate wearing out. As the blue element goes away ... it starts to look like the other edge of the image has a purple tinge to it. Actually what is really happening is the blue is going away faster in the middle than the edges.

    Put up a gray pattern like a typical overscan charge or resolution chart ... and examine the image for discoloration.

    Poor ventilation usually speeds up the discoloration ... aka the break down of the plate. The plate costs about $100 to replace yourself. A worn out polarizer looks like a film frame where someone has put a match to the center and have it burn outward ...

    This is a limitation of the LCD technology for your generation and those before it. Newer units may go to different compounds for the polarizer that is less prone to breaking down. It's the UV light coming off the bulb that does this.

    DLP of course does not have this issue ... but it has its own other issues.

    regards
     
  5. Greg Bright

    Greg Bright Second Unit

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    My 500 has developed 2 greenish areas near the bottom of the picture midway between the center and the sides. Anybody have any ideas as to what might be causing this? My new bulb only has a few hundred hours on it.

    Thanks
     
  6. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Green blobs usually indicate dust blobs ... clean out the lamp compartment first and then see if it is still there.

    Regards
     
  7. Greg Bright

    Greg Bright Second Unit

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    Thanks very much for your input, Michael; but I'm not convinced that these abberations are dust blobs which I've had before. These start at the bottom of the screen in the same place on both sides of center and get narrower as they go up about one-quarter way, symetrically. Sort of like Sugar Loaf mountain in South America. Maybe the LCD panels actually need cleaned. Or the inside of the lens. Got close to 3000 hours on it. I will give it a thorough cleaning and inform of the results.
     

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