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AV and Multimedia Related Thread, White spots on projector in Technical; We have a Sanyo PDG-DSU21b projector, and over time, white spots have started to appear on the projected image. I ...
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    White spots on projector

    We have a Sanyo PDG-DSU21b projector, and over time, white spots have started to appear on the projected image. I would guess it is dust? But where?

    I have changed the bulb and cleaned the external glass of the lens. But the white spots remain. Could it be something else?

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    You would not get white spots from dust , dust would stop light, white spots would be faulty display, i would need more info to advise further.

    Marc
    Projector Engineer

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    Thanks, I'll get a picture later to show you what I mean

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    Quote Originally Posted by sidewinder View Post
    I have changed the bulb and cleaned the external glass of the lens. But the white spots remain. Could it be something else?
    Sadfully, the general answer is a pixel is dead. Bearing in mind the lamp only shines light "through" the LCD screen normally, it will just go through as white light.

    Steve

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    Oh dear. I'll have to find out how old the projector is, it doesnt look that old but I guess it could be. Would it be covered by the warranty if it is still in it?

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    Generally I think it depends on company/warranty etc, Some say up to 5~ pixels is "norm", some don't etc

    Might be worth checking a few other ideas first, but pretty much sounds like dead pixel. Is it a lot that are dead? or just 1-2?

    Steve

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    Oh so it is similar to actual LCD screens then?
    It is a lot, there is a scattering of them over one side of the board - think it has got progressively worse

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    Quote Originally Posted by sidewinder View Post
    Oh so it is similar to actual LCD screens then?
    It is a lot, there is a scattering of them over one side of the board - think it has got progressively worse
    Well simple version, the lights split (3 colours etc), passed through the LCD screen, which obviously stops certain colours etc etc.

    If it's dead pixel, aka always "off" its never blocked, so white light.

    Guess it might be worth checking with the warranty/supplier.

    Steve

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    I meant similar to LCD screens in that a certain amount of dead pixels is considered acceptable - I've never seen them on a projector before so didnt realise

    Attached an image that shows it fairly well, also some of them flicker a bit

    IMG_20110407_115921.jpg

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    Ah my bad, but yeah looks like them. Be good to know how the suppliers act on the warranty side. "Normal wear" complaints inc :P

    Steve

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    In therory your right but in practice you would have to have a pixel in each screen in the same place to get a white light, so if your right i would go buy a lottery ticket as it would be a one in a milliion chance, but seriously i am interested to see what it is, i have repaired hundreds of these and NEVER seen a white pixel LCD problem i think it more likley to be a contoller issue, but get me a photo and or if you lke i will ring you to get to the bottom of it PM me and i can ring you.

    Marc
    Projector Engineer

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    A tad bit late to this thread but was wondering if a solution to the issue of white pixels appearing in clusters was found. I have an Optoma DLP projector and have recently encountered the same problem, the white dots also appear to be increasing in quantity so a response would be much appreciated.

    Thanks!

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    elsiegee40's Avatar
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    I'm afraid the only solution to dead pixels is to send it back for repair @sonobenissimo

    I had this on a Casio LED projector which was under guarantee fortunately... they do get progressively worse once it has started too

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    Yes they do get worse we call it creaping coruption, as it seems to grow once started (oh dear another DLP), if its not uner warranty then it will be a replacement, sorry.

    Marc
    Projector Engineer

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    I have seen this problem in a lot of infocus and sharp projectors. It is a defective DLP chip, however I have never sent one in for repair so I don't know how expensive it would be. Also I've never been able to order a replacement DLP chip from any vendor either.



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