Connect with us

Horizontal "Smearing"

Discussion in 'Electronic Repair' started by JoN, May 18, 2004.

Scroll to continue with content
  1. JoN

    JoN Guest

    Hi!

    I have a Toshiba CF3254J that currently has bright horizontal bands
    that seem to eminate from any light colored objects on the screen, be
    they in the displayed images (movie, etc) or the tv's function display
    (volume bar, channel, etc).

    The vertical had been squashed completely from the lower half into the
    upper half, but that is better now that I replaced two capacitors
    (c301 and c305). Does anyone have any idea what could be causing the
    current condition? Could it be something adjustable, or more
    capacitors, or what?

    Any help pointing me in possible directions to proceed would be
    greatly appreciated.

    Thank You in Advance,

    Jon O. Noble
     
  2. john

    john Guest

    Did the picture have the Smearing before you changed the Caps ?

    kip
     
  3. Jerry G.

    Jerry G. Guest

    This is sometimes attributed to a frequency response problem in the video
    path. If the smearing is on all colours or is of a white or grey in
    character, then it is common to all 3 colour channels. This then can be
    something to do with the luminance processing, or is the same for all 3
    colour channels. A common cause in the video circuits are capacitors that
    have become high in their ESR. Another very common cause is a CRT that is
    going weak.

    --

    Jerry G.
    =====


    Hi!

    I have a Toshiba CF3254J that currently has bright horizontal bands
    that seem to eminate from any light colored objects on the screen, be
    they in the displayed images (movie, etc) or the tv's function display
    (volume bar, channel, etc).

    The vertical had been squashed completely from the lower half into the
    upper half, but that is better now that I replaced two capacitors
    (c301 and c305). Does anyone have any idea what could be causing the
    current condition? Could it be something adjustable, or more
    capacitors, or what?

    Any help pointing me in possible directions to proceed would be
    greatly appreciated.

    Thank You in Advance,

    Jon O. Noble
     
  4. Art

    Art Guest

    Troubleshoot the video processing, G-2 voltage source, etc. Also try
    adjusting the Screen Control, if the problem is becomes more severe with
    changes of the screen control position you may be looking at emission
    related failure within the crt itself. If available try unsing a good scope
    to trace the video from the demodulator (Jungle ic) out to the crt, the
    smear, if caused bu the video circuitry, should be aparent. May even be
    caused within the jungel Ic and associated components.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-