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    Need capacitor parameters or schema!

    My LG 42LW5700 doesn't power on. when tv plugged on the standby light is a very week until I switch power on the standby light blinking slowly

    after checking the power board supply,
    I suspect the ceramic capacitor CY101 that have a 0 ohm resistant.
    On P201 I got on pwr-on 3.3V instead of 24V.
    I cannot find the board schematic on the web.
    and I can not figure out which parameters is it?
    please see the picture below.

    Any help from the experts will be appreciated.
    Thanks!
    Attached Files
    Last edited by atari1968; 08-06-2019, 03:03 PM.

    #2
    Re: Need capacitor parameters or schema!

    Originally posted by atari1968 View Post
    My LG 42LW5700 doesn't power on. when tv plugged on the standby light is a very week until I switch power on the standby light blinking slowly

    after checking the power board supply,
    I suspect the ceramic capacitor CY101 that have a 0 ohm resistant.
    On P201 I got on pwr-on 3.3V instead of 24V.
    I cannot find the board schematic on the web.
    and I can not figure out which parameters is it?
    please see the picture below.

    Any help from the experts will be appreciated.
    Thanks!
    1) You have two row of pins, the exposed pins you see on top are the ODD number pins, the EVEN number pins you cannot see from the topside of the board, you have to use skinny probe to probe the Voltage on the wire entrance side of the connector.
    2) PWR-ON should be around 2 ~ 3.5V, the 24V lablel is not for the PWR-ON pin, it is for the switched 24V power supply pin.
    3) Right now you have PWR-ON signal from main board to turn on the switched supplies but the switched 24V does not come on.
    4) You need to measure the Voltages on ALL the pins of P201 again since you are not reporting all the pins, it has 24 pins total.
    5) CY101 is safety cap, remove it and measure its DC resistance again, it is not needed for the TV to function.
    Last edited by budm; 08-06-2019, 05:11 PM.
    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: Need capacitor parameters or schema!

      I measured the output voltage after switch on and everything looks okay although the weird safety capacitor (CY101) show 0 volts in switch on while the others (CY102-104) show 220 volts.
      Please see the attached picture of the voltage test for the output ports.
      Thanks for your help
      Attached Files
      Last edited by atari1968; 08-07-2019, 02:57 PM.

      Comment


        #4
        Re: LG TV 42LW5700 does not power on fully

        Thanks #budm


        So probably the power supply is ok and the problem could be on the mainboard EAX64405501,
        The led is always very dim until I switch on and then the led start to blink (high and dim not in the same rate).
        What do you think from the measure? What do I need to check next?

        Thanks for any help
        Attached Files

        Comment

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