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Toshiba 43" rear projection HELP

Discussion in 'Electronic Repair' started by Ron, Jun 1, 2005.

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  1. Ron

    Ron Guest

    I just aquired a Toshiba 43" rear projections television Model TP43H60
    using chasis TAC9859. Upon plugging it in I hear the high voltage kick
    in. All three tubes glow. But no picture. I removed the front panel
    to reveal the control knobs for the flybacks. I toned them up a bit...
    now I get a pictures with a horizontal line across. then after a few
    seconds it scatters like a oval type shape. My thoughts since I repair
    video game monitors for my work.. I suspected the horizonal output
    transitor. Any help would be great.

  2. Ron

    Ron Guest

    Also I saw a D2253 transistor... is this the HOT?

  3. James Sweet

    James Sweet Guest

    If you have any picture at all then the HOT is obviously good. What do you
    mean by the pic scattering? Do you have a way of measuring the HV?
  4. Art

    Art Guest

    Try disconnecting the convergence yoke wires at the convergence correction
    area of the deflection pwb. Pay attention as to which connector goes to
    which plug. There are three, one for red, blue,and green. If you get a full
    raster with video then it is probable the output ics have gone bad and need
    replaced. The display will be distorted because the correction for
    registration will not be present. Pay attention to the small value resistors
    in that circuit also.
  5. Ron

    Ron Guest

    when the unit is powered on it will have a straight line (red green and
    blue) from right to left, then I hear a click and it will look like an
    oval type shape. Red on the other hand starts to fan out like a
    chinese fan on each side from the center (about 6-7 inches) I'm going
    to get a few pictures and post them with links on my webserver today.

  6. Ron

    Ron Guest

    unplugging the three connectors I get no picture. I plugged one in at
    a time and each appear to look like a star. then I plugged two in and
    I seen the straight line from left to right. then I plugged them all
    back in to get where I was.. I'll check resistor values later on
    tonight when I get some time.

  7. Ron

    Ron Guest

    grr.. I posted two pictures and it didn't post to the groups...


    Remove the ** of course..

  8. Rono

    Rono Guest

    You have no vertical deflection. Bad connections, or
    bad IC, these units are known for bad convergence IC's
    also. Rono.
  9. James Sweet

    James Sweet Guest

    That's pretty screwy, at any rate horizontal deflection is fine, it's
    obviously a vertical problem of some sort, actually pretty likely the
    vertical output IC is toast, the vertical deflection you are getting could
    be from the convergence yokes.
  10. Ron

    Ron Guest

    Update: Well I've replaced both STK392-110s with no change in the
    picture. Does anyone have or can download a schematic for this unit..
    the model number is TP43H60 Using Chassis TAC9859. I have one
    capacitor in question C446... Can anyone verify that D688 is the
    vertical output transistor?


    Thanks for all the help.
  11. kip

    kip Guest

    Have you checked the return resistors , are there any PC mount fuses ?

  12. Ron

    Ron Guest

    Checked all resistors (the 1 ohm and 3.3 ohm)... All check out ok. My
    guess at this point would be this missing capacitor... I used my volt
    meter to check voltage. I get about 210-220 volts DC on the positive
    side of the cap. I've traced the negitive side of the cap all the way
    back to the flyback. of course it jumps though hoops a capacitor here
    and a diode. I've tried to install a 200v 1uf cap. with no change in
    the picture.

    Baffled but learning in the process.
  13. Art

    Art Guest

    Possible the Convergence DCU is defective?
  14. Ron

    Ron Guest

    I was told this DCU unit rarely fails. I need to find the value of
    C440. My unit seems to be missing this Capacitor for some reason. If
    anyone has a schematic or knows the value I would most appricate it.
    No one here locally has any schematics... so I reach out to those on
    the web for assitance. Anyone with access to the schematic or has a
    PDF of it I would appricate it. Toshibia points me to a service
    center. But I haven't heard any response.

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