Blue and red "dust clouds" on CRT display

Discussion in 'General TV Discussions Forum' started by clemenzina, Jan 29, 2009.

  1. clemenzina

    clemenzina
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    I would like to know if this is anything to worry about and why it happens.

    DAEWOO DUB2850 28" CRT DTV

    Soon after buying this TV I noticed that when there was a white background (best demo was on Freeview 22 Ideal World shopping channel, their left-hand white panel showing item details) there gradually appeared a blue/grey "cloud" roughly circular. If I changed channels a dark patch would remain, gradually fading.

    Daewoo sent an engineer (contractor) who turned up on a Saturday morning when Ideal World were using different graphics and I couldn't show it on live TV but I showed him a recording - to cut a long story short, he sneered at me and refused to believe it was anything other than my PVR that was at fault.

    Now that I'm using Tiscali's PVR and they have the recording library displayed on a white background, I can see that there are actually 2 "clouds", the left-hand one is blue-grey and the right-hand one is reddish-grey. Each takes up almost half the screen. I've just reproduced it on the TV's own "feed" - sod's law I have perfect conditions today with no-one to witness it.

    Apart from the time it takes for the patches to fade, it causes no problems (yet), the PQ is generally very good.

    TV's out of warranty now - doesn't time fly? :rolleyes: Sorry to be so wordy, but it's bugging me so I'm bugging you ;)

    clemenzina
     
  2. NST

    NST
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    Sounds like a colour purity issue to me. Normally if the effect is not severe, it can be caused by items in close proximity to the TV, such as mains wiring/ cables, unshielded Hi-Fi speakers, mains operated equipment on top of the TV etc.
    These give off magnetic/ electromagnetic energy that can cause this type of problem. Try the following:

    1. Unplug the set from the wall for at least an hour, then switch on again. Do not leave the set in stand-by for long periods when not in use.
    2. Move any aformentioned objects away from the TV
    3. Re-position the TV somewhere else in the room

    Try these first and see how you go :smashin:
     
    Last edited: Jan 29, 2009
  3. radioredcat

    radioredcat
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    I think your problem is the shadow mask is warping under high brightness levels.
    Try experimenting by reducing the brighness and contrast a little at a time till you get a comromise.
    In the past iv'e looked at peoples tv's and found that they had not altered any settings since they bought it and iv'e the brighness way over the top causing these problems and also focusing problems as well.


    andy
     
  4. clemenzina

    clemenzina
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    Thank you both!

    I cannot move the TV (I had to pay the delivery company £40 to bring it upstairs and the chaps £10 to take it out of the box and put it on my 'shelf' :( )

    There is a stack of PVRs and a DVD/HDD recorder sitting 6" to one side the TV - nowhere else to put them :(

    I find the picture adjustment difficult to understand - I've messed around with it a lot. One thing I can say - my settings are on the dull side, I don't do bright or garish. Oh for my old Samsung where I had a toggle button for Standard/Dynamic/Movie/Mild/Custom.

    You've got me thinking, though - the TV is an ex-display model, I bet they had it set really bright in the showroom :eek:

    I will try to obey you both - switch the darn thing off more often, and venture back into the picture settings.

    Thank yous ;)

    I'm going to do another post soon about the sound, beware ;)

    clemenzina
     

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