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sharp lc-45gd4u No Video, No Sound at first

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    sharp lc-45gd4u No Video, No Sound at first

    I'm working on a sharp lc-45gd4u LCD TV that after power up, has no video and no sound, but has back lights. It turns off after about 30-45 seconds.

    According to the owner, if he turns it on an off a number of times, it will eventually come on. He says the amount of time it takes to come on is getting increasingly longer, and is now over an hour.

    I did see the TV on and when it's on, it works fine. It can be turned off and back on within a few minutes, but if it stays off more than about 10 minutes, you have to turn it on and off for another hour to get it back on.

    I don't see any leaking caps on the power supply board and all PS voltages seem to be there. The PS_ON is working, since the back lights light up.

    The increasing time to come on sounds like a failing cap, but isn't the power up digitally controlled by the main processor?

    This is an older TV with a bunch of boards, some of which are very difficult to access/remove.

    Anybody have any suggestions?

    Thanks!

    #2
    Re: sharp lc-45gd4u No Video, No Sound at first

    Service manual:
    http://elektrotanya.com/?q=showresul...at2=schematics
    Never stop learning
    Basic LCD TV and Monitor troubleshooting guides.
    http://www.badcaps.net/forum/showthr...956#post305956

    Voltage Regulator (LDO) testing:
    http://www.badcaps.net/forum/showthr...999#post300999

    Inverter testing using old CFL:
    http://www.badcaps.net/forum/showthr...er+testing+cfl

    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
    http://s807.photobucket.com/user/budm/library/

    TV Factory reset codes listing:
    http://www.badcaps.net/forum/showthread.php?t=24809

    Comment


      #3
      Re: sharp lc-45gd4u No Video, No Sound at first

      You could try heating each board(testing for operation before moving to next) with a hair dryer to narrow it down.

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