What else could it be

Discussion in 'General Electronics Chat' started by Interested, Mar 1, 2010.

  1. Interested

    Thread Starter New Member

    Feb 12, 2010
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    Hi guys
    i have a problem with a panasonic 20 inch colour tv board no.ADP 269
    the problem is i have a thin straight line across the screen when it is powered up witch indicates to me that i have a vertical problem.
    I check all the components in that circuit which tested to be ok,
    I change the vertical deflection ic no.la7835 but to no avail. Could someone point me to the next possible step.
    Thanks in advance :(
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    I'd start by getting a Howard W. Sam's Photofact schematic for it, if you don't have one already. They will save you a lot of head-scratching. They are not free, but your time is worth something, too.

    Website: http://www.samswebsite.com/photofacts.html
     
  3. ifixit

    Distinguished Member

    Nov 20, 2008
    639
    108
    Open circuit in the vertical deflection coil.
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    First and for most, never leave the set open with a bright line in the middle even when trouble shooting, This will damage the phosphor, and you will end up a visible vertical line . Always limit the brightness or screen so that the line is barely visible to the eye and work.
    Second get a schematic for it, if you cannot find then post back, I'll see what I can do.
    Third is that you should know your way around a TV and should have proper soldering practice when repairing a TV.
     
  5. loosewire

    AAC Fanatic!

    Apr 25, 2008
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    Does it have deflection yoke on the neck of the.picture tube.
    If you have a white line your high voltage is o.k. don't
    mess with it,you will end up with more problems.
     
  6. jgessling

    Active Member

    Jul 31, 2009
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    14
    I found out recently that our local library has the Photofact docs. Shelves full of them going back to the late 40's. I grabbed a copy of the schematic of my 1945 Emerson battery powered tube radio. Just paid a few coins to use the copier. Check around, maybe your library can get them for you.
     
  7. Interested

    Thread Starter New Member

    Feb 12, 2010
    7
    0

    Thanks for the info.
    I tried searching for the schematic but found none. Yes i know a bit about tv`s and i have very good soldering skills. I attend classes of television repair crt that is, but i want to impress my instructor by figuring this one out by myself and with the help of you guys.
     
  8. Interested

    Thread Starter New Member

    Feb 12, 2010
    7
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    Vertical deflection yolk tested ok
     
  9. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    can you take pictures plus I need the TV model no.
     
  10. Interested

    Thread Starter New Member

    Feb 12, 2010
    7
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    Model no.--- ct-20R13U
    will get pics later
     
  11. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    http://www.owner-manuals.com/index....eyword=ct-20R13U+service+manual&forward=plist

    I have searched for the service manual and it seems that one have to buy it, above is a link that I found.

    Now when it comes to repairing CRT's, one should have the service manual so that one can speed up the process.
    And if you get stuck I should have something to refer so that I can guide you to repair the TV.
    I am confident enuf that I can fix the TV, but in this situation you are the puppet :p.
    In order to pull the strings we need the diagram.
    So if you want it to be repaired then get the service manual, If I had it I would post it, Panasonic manuals are very rare indeed

    PS. I think I sound like loosewire.
     
  12. bertus

    Administrator

    Apr 5, 2008
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  13. Interested

    Thread Starter New Member

    Feb 12, 2010
    7
    0
    Thanks to all you guys for the inputs, it really helped.
    Problem solved. After all parts tested good, there was a cold solder at the power ic
     
  14. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Sometimes it's the simple things that bite you.

    Glad you figured it out and got it fixed.
     
  15. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    760
    Dido :cool:
     
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