philips 9616 weird effect?

Discussion in 'General TV Discussions Forum' started by Bob Todd, Jul 3, 2002.

  1. Bob Todd

    Bob Todd
    Banned

    Joined:
    Aug 20, 2000
    Messages:
    3,109
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    UK
    Ratings:
    +369
    I have noticed at times the picture has an embossed shadow effect on the right hand side of say a face.

    is this normal?
    can it be fixed?
     
  2. philipb

    philipb
    Active Member

    Joined:
    Mar 6, 2002
    Messages:
    2,091
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    63
    Location:
    Swindon
    Ratings:
    +172
    Just a stab, but how high do you have the sharpness set? Try turning it right down and see if that helps.

    If not it might be an artefact of the incoming signal - RF can give you that effect, its called ghosting I think. Do you get it on all inputs - DVDs say - as well?
     
  3. Zacabeb

    Zacabeb
    Active Member

    Joined:
    Jan 17, 2002
    Messages:
    474
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    21
    Ratings:
    +9
    Also check the contrast level. If the contrast is high, it will overdrive the SVM and LTP circuits leading to ringing. This is an intentional effect which can not be turned off without internal modification to the set.

    I call it the Duckburg effect.

    SVM, or Scan Velocity Modulation, uses an extra pair of coils on the electron gun, behind the deflection coil. The SVM coils offset the electron beam before it is deflected. The current to the SVM coils is varied according to the picture content, with the result being that bright parts are shrunk and dark parts are inflated. This intends to compensate for the spot blooming that occur at high contrast levels.

    However, SVM is almost always overused. In strong transitions in contrast, this may lead to the edges of faces or other objects being literally cut out of the background and shrunk, to form an overly bright edge - along with the jet-black outline. Also, SVM might be too slow when there are several transients in contrast rapidly following one another. That leads to small details being shifted out of place. Text for instance may be affected, with some characters bending to the shape of the characters preceding them.

    If there is existing ringing around edges in the picture, such as from an off-air signal, SVM happily amplifies them into monstrosity.

    The are but two ways to overcome this.

    1.) Having a technician physically remove the SVM connectors inside the set.
    2.) Turning down the contast to at least reduce the SVM artifacts. Your eyes may adapt to the lower contrast, and so does SVM.

    Generally, I think you should keep contrast at between 30-50% on the set, assuming Active Control is off or at least below max. When Active Control is at max, it turns on the light sensor. Then the range of useful contrast will vary depending on the ambient light.

    The set is designed to have the light sensor on. If it is off, the contrast range will stretch way too far, so far in fact the peak white limiter kicks in. Then think of the halfway point of the contast scale as being 100% and anything above being there just for Spinal Tap.
     
  4. Bob Todd

    Bob Todd
    Banned

    Joined:
    Aug 20, 2000
    Messages:
    3,109
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    UK
    Ratings:
    +369
    Its on all sources DVD, NTL


    will give these a try, and let you know of the outcome.

    thanx

    just got the dolby digital working so I am playing around a bit here
     
  5. Bob Todd

    Bob Todd
    Banned

    Joined:
    Aug 20, 2000
    Messages:
    3,109
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    UK
    Ratings:
    +369
    cant seem to shake the shadow effect

    damn wish I had gone for the panasonic TX28PB50 noW:(

    so If i tell the enginneer to remove SVM will i lose anything?
     

Share This Page

Loading...
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice