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Grundig 40VLE7131BF led strips doesn't light up

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    Grundig 40VLE7131BF led strips doesn't light up

    Hi guys,
    I have one very old TV.
    Main problem I have with this tv is that led strips won't light.
    I measured voltage levels, and inverter input is 24V.
    other voltages are also ok.
    What I found is that removing and connecting again connector CN1 led strips lights for shorts time (but only once). When led strips lights up then light is uniformly spread on whole panel.
    First I thought that led strips are dead, but I'm quite sure that problem is not strips related.
    I don't know what voltage level is at output of inverter board (samsung SSL400_3E2A) and how to measure voltage of LED1, LED2, LED3 and LED4.
    Measuring inverter output for lines LED1...4 to the ground while CN3 is connected (steady state) gives voltage levels as below:
    1. LED1->GND = 10.98V
    2. LED2->GND = 2.83V
    3. LED3->GND = 10.98V
    4. LED4->GND = 2.83V
    5. VCC->GND = 5.4V

    Voltage level at inverter board input is very stable and at 24.6V (no matter is display flicker or in steady state - stay sable).
    On inverter board there is CN2 connector where I can see signals as follows:
    1. GND
    2. PWM
    3. 3D_ENA
    4. V_SYNC
    I suppose that PWM is for display panel brightness, V_Sync is some signal for synchronization. Of course I can not measure nothing there because I don't have equipment here.
    Is it possible that two stripes (LED2 and LED4) create this behavior of inverter board, or this is inverter feature (regarding voltage output)?
    One note is that during removing and inserting CN1 connector inverter voltage output changes so VCC jumps to 24V, then even 60V. I suppose that this is because transient state. After second or a little more every voltages come to mentioned values.
    I will be thankful for any help.
    Inverter board is quite cheap but I want to be sure, if possible of course, to not buy something which is not broken...
    Please find attached pictures of boards.
    https://photos.app.goo.gl/DSQJ9k4wFaYdek2y6
    Thanks in advance.
    Last edited by h4rdw4re; 10-09-2022, 11:56 AM.

    #2
    Re: Grundig 40VLE7131BF led strips doesn't light up

    Check your pins on the board for cracked joints.
    I assume no responsibility for any stupid suggestions I might post.

    Comment


      #3
      Re: Grundig 40VLE7131BF led strips doesn't light up

      prolly bad backlights, compared to a lot of tvs it speaks very well that they lasted this long.

      Comment


        #4
        Re: Grundig 40VLE7131BF led strips doesn't light up

        Originally posted by nomoresonys View Post
        prolly bad backlights, compared to a lot of tvs it speaks very well that they lasted this long.
        Hello everyone,
        Just an update regarding led strips.
        After replacing led strips TV started working correctly.
        Thanks for helping me.

        Comment


          #5
          Re: Grundig 40VLE7131BF led strips doesn't light up

          well done .i hope you find something worth watching on it .

          Comment

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