LG 452 Monitor

Discussion in 'General Electronics Chat' started by tonydix, Sep 10, 2011.

  1. tonydix

    Thread Starter New Member

    May 4, 2010
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    0
    This monitor will not start. On application of power the power led and all the other front panel leds light up briefly for about 1 sec. They then turn off and about 2 secs later they light up again. This cycling continues indefinitely.
    The Mofset in the smps has been removed and checks out ok.
    Careful visual inspection shows no obvious damage. I suspect SMPS shutdown due to another fault condition. No schematic available !
    Any ideas would be most welcome
    Thanks
    Tony
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    You want us to guide you or ?
     
  3. tonydix

    Thread Starter New Member

    May 4, 2010
    23
    0
    Any ideas about how to proceed would be much appreciated. Scope signals on various pins of the smps transformer indicate a square wave with some pins showing a dc jump in voltage in sequence with the flashing leds. A similar jump in voltage is detected on the main smothing capacitor after the diode bridge Without a schematic I am unable to work out what protection circuits exist on this chassis
    Thanks
    Tony
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    I have to see it to tell u what to do.
     
  5. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    Show me the works mate
     
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