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Very old monitor repair

Discussion in 'Electronic Repair' started by CIP, Mar 2, 2005.

  1. CIP

    CIP Guest

    Hi everybody,

    I got an very old monochrome monitor that is dead.

    It's an NEC BU-1201M(E)-1 from about 1985

    It had an burnout fuse on the main board, replaced it but the screen remains
    black. Audio works. When I switch it on the first second the end of the CTR
    lights up but then it gets very dim or even no light at all. I can hear the
    HV make a little hunnimg noise.

    It's a monitor from a computer that controls a factory. The monitor was
    turned on in 1985 and never turned off, but when not in use the screen was
    cleared. The video input is NTSC

    Checked the power transistors (h/v) and they are ok. Transformer is ok.

    Anybody any tips?
     
  2. Aidan Grey

    Aidan Grey Guest

    NTSC is standard North American TV video. What you have essentially is a
    monochrome
    TV being used as a monitor.

    You should be able to be able to cheaply buy a replacement TV type monitor.
    One
    place to check is video security monitors. A security camera being recorded
    on a
    VCR is using an NTSC signal. The video monitor for such a task would
    probably be
    a drop in replacement for your defective monitor.

    Note that even if you could repair this monitor, it will not be reliable at
    its age. A brand
    new monitor will give you the reliability needed for a factory environment.


    Aidan Grey
     
  3. Clint Sharp

    Clint Sharp Guest

    The HV shouldn't hum, it should whistle, you can check for operation of
    the flyback transformer by holding a neon screwdriver close to the
    transformer, it should glow on a monochrome unit if it's running.
    Replace it, if it's in a factory it's needed! You could probably replace
    it with a 12" PAL Unit and get away with it with a couple of minor
    tweaks to the frame rate and line sync. http://rswww.com supply chassis
    monitors as do many other 'industrial' electronics component suppliers.
     
  4. James Sweet

    James Sweet Guest

    Don't forget that there might be special mounting considerations.

    Also I would not nessesarily expect a modern TV to last anywhere near as
    long as that monitor did, if the image was still reasonably good I'd repair
    it personally.
     
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