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CTC169

Discussion in 'Electronic Repair' started by [email protected], Mar 3, 2007.

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  1. Guest

    First off, let me say that I'm not a TV tech.... I'm an elec. eng. who
    does controls for a living.

    Anyhow, I got this dead RCA set for free and am working on it for fun
    and to learn.

    The TV: RCA colortrack 2000 invar CHASIS CTC169


    The set was initially dead. After reading through many postings in
    this group... I have done the following troubleshooting and replaced
    the following components.

    Failed components found:

    blown 5A inline fuse
    Open flame proof resistor 2.5 ohm (if i remember correctly)
    Shorted B+ regulator


    Components replaced: (based on my internet reading)

    Above mentioned parts plus....

    CR4118
    U4101
    C4102
    C4104
    C4108


    The set is no longer dead but presents some odd symptoms. The set
    powers up.... audio is fine. The first thing I see is a horizontal
    green line across the screen which is shortly replaced by a picture.
    The picture and menus are darker then they should be and are
    vertically stretched. If I do an autoprogram (channel search), the
    picture will return to a normal size, but will remain on the dark side
    with the menus showing up in dark blue which is barely visible. Once,
    the set is powered down and back up, the picture is once again
    vertically stretched and cured by autoprogram.

    I've measured the cathode voltages of CR4118 & CR4116 to the ground
    around the picture tube. The voltage readings are 12.47 and 135
    respectively Based on my reading, these sound a bit low, but I'm not
    sure where to go from here. I have followed the ground path around
    the board and cleaned up some solder joints, but the symptoms
    persist. Any thoughts?

    Thanks
    Bob
     
  2. Bob, I have even less qualifications than you to open up a TV set, but I
    just finished fixing the remote receiving unit on a 1987 Mitsubishi set.
    In the course of the repair I discovered two switches on the printed
    circuit board mounted on the end of the cathode ray tube. They are both
    three-position switches and while manipulating the main circuit board
    with all its wiring I managed to move one of them to the wrong position.

    I ended up with a single horizontal line across the middle of the tube.
    After resetting it and getting back the whole picture, I flipped them
    both all three ways to see what happens. The color changed as if the
    blue or red had been lost. So I flipped them back to where everything
    was good. This may or may not have anything to do with your problem, but
    you may find this site helpful. It's where I learned about those
    switches and where they are located:

    Sci.Electronics.Repair FAQ: Main Table of Contents
    http://www.repairfaq.org/REPAIR/F_Repair.html

    Scroll down to where it reads:

    Television Sets (new segmented, includes download link) | (latest whole
    - slow)

    Lots of great troubleshooting info there.

    Good luck,
    Jack
     
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