Television damaged by speakers?

Discussion in 'Home Cinema Buying & Building' started by dmort25, Jan 5, 2005.

  1. dmort25

    dmort25
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    Hello,

    I've just bought an all-in-one system, and am experiencing some screen distortion.

    There is no noticable distortion when watching standard television channels,
    but when a dvd is played, a colour distortion slowly appears. This seems to
    occur in areas which stay bright for long periods (e.g. dvd selection/title screens).

    The distortion will then fade, when a normal picture resumes. This happens even when the t.v. is not near the speakers, or if the speakers are
    turned off. The effect is a greenish blob to the left of the screen, and a purple blob to the right.

    Why would this occur, and only when watching dvds? Could the fact that the dvd it is a higher quality signal than t.v. have something to do with it?

    Up until recently two stereo speakers (probably unshielded) were positioned to either side of the t.v. Could this have magnitised the screen in some way, and damaged it?

    If this is the case, I would have expected the distortion to be permanent rather than random. Is this correct?

    If anyone has any thoughts which might explain this, please respond.

    Thanks,
    Dave
     
  2. Greg Hook

    Greg Hook
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    Unshielded speakers near a TV are not a good idea. My speakers are shielded but when I got my first sub which wasn't, moved it near the TV and a big purple blob appeared. Fortunately it went away.

    I would imagine the speakers you had before were probably shielded as I think they would have messed up the TV after a while, perhaps the speakers on this all in one are unshielded. Can you check in the manual to see?
     
  3. jerryq7777

    jerryq7777
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    If it only happens with the dvd player then thats the problem i would have thought.Check the scart connection is fully home (if it has one) and try another dvd player to see if it repeats the problem.If its still under warranty get it repaired.
     
  4. GaryB

    GaryB
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    If this only happens after bright areas have been on screen for a while and is visible but slowly disappears when the scene is changed, it is shadowmask doming. It is caused by heating of the metal shadowmask just behind the front face of the tube by the high beam current. You should also find that it will show up if you get a large white area displayed on a teletext page.

    Do a Google search on "shadowmask doming" for lots of info.
     
  5. CYRUStheVIRUS

    CYRUStheVIRUS
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    The TV just needs degausing, have you tried turning it on and off a few times.
    And obviously move the speakers further away.
     
  6. GaryB

    GaryB
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    If the TV just needed degaussing, the purity problems would be there all the time. The fact that they show on bright areas and then gradually disappear is an indicator of doming.
     
  7. CYRUStheVIRUS

    CYRUStheVIRUS
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    Is the dvd player part of the all in one, can you try another one?
    The green and purple is common with unshielded equipment near the T.V.
    But i am no expert ;)
     
  8. thewul

    thewul
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    yep i`ll go with doming, new crt may or may not put it right, try turning your brightness down a bit, it may help but there is no cure
     

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