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CRT pinout for toshiba TV?

Discussion in 'Electronic Repair' started by John, Jun 6, 2006.

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  1. John

    John Guest

    Have a toshiba cd35d60 with a green gun that sometimes doesn't fire -- the
    screen would turn magenta.
    Sometimes it cycles between normal and magenta while on.
    Poking the CRT neck circuit board with a plastic stick restores the green
    color, for a
    short while. It seems to be a bad contact.

    I cleaned the pins on the CRT and put back the neck circuit board, but the
    problem remains.

    Where can I find a pinout diagram for the CRT (model A89LFL50X02)? If I can
    identify the green cathode pin, then I can concentrate on it -- perhaps
    solder a wire from that pin directly to the neck board.
     
  2. Tech Data

    Tech Data Guest

    If you'll put the stick away and get out a dc meter, you could find the
    pin yourself. Follow the collector of the 3 larger transistors to where
    they route to the socket. Blue on top right, green towards center and
    then red. When working, dc volts should be between 120 and 150. When
    the green is not working, then that pin should read between 180 and
    200. My money is on a bad solder connection on the board itself. Of
    course, that's probably not near as much fun as hitting it with a stick
    and soldering a wire to the picture tube but, that's how technicians
    would normally go about it.

    www.techdata-kicksass.net
     
  3. pin 5 G1
    pin 6 Green
    pin 7 G2
    pin 8 Red
    pin 9 filament
    pin 10 filament
    pin 11 Blue

    According to the Sencore setup book.

    Leonard
     
  4. ian field

    ian field Guest

    Resolder all the joints on the CRT-PCB - intermittent dry-joints have become
    routine since manufacturers started using lead free solder, especially where
    there is temperature cycling like from the CRT heater!
     
  5. John

    John Guest

    After reading the first two responses, I went looking for bad solder joints
    on the neck board and saw nothing obvious. I went ahead and resolder the
    joints starting from the green cathode pin to the driving transistor. Some
    of the joints looked suspicious (the solder bead up around the component
    pin), so I made sure the new solder spread.

    I also polished the CRT pin (it turn blued) and applied a thin layer of
    solder to it.

    After that, the TV has been working fine for two days. Can't conclusively
    say it is fixed, but looks promising -- previously it has never lasted more
    than 2 hours without losing the green.

    Thanks to all who responded.
     
  6. ian field

    ian field Guest

    One of the features of lead free solder is that a bad joint can still look
    ok!
     
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