LG 42LG50 no backlight or display

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  • syaoran123
    Senior Member
    • Jun 2014
    • 178
    • Australia
    #41
    Re: LG 42LG50 no backlight or display

    Did you recap the electrolytic capacitors on the top right? Also test the two blue film capacitors on the bottom right to see if they match the ratings.

      Comment

      • lookimback
        Badcaps Legend
        • Aug 2013
        • 1489
        • USA
        #42
        Re: LG 42LG50 no backlight or display

        Originally posted by syaoran123
        Did you recap the electrolytic capacitors on the top right? Also test the two blue film capacitors on the bottom right to see if they match the ratings.
        He's already gotten the backlights to turn on by disconnecting the top ribbon cable from the t-con. I'd say that rules out any problems with the power supply. He tried a t-con, and got the same readings from the replacement. That leads me to believe that both are ok. I think it comes down to the main board or the master inverter.
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          • syaoran123
            Senior Member
            • Jun 2014
            • 178
            • Australia
            #43
            Re: LG 42LG50 no backlight or display

            Originally posted by lookimback
            He's already gotten the backlights to turn on by disconnecting the top ribbon cable from the t-con. I'd say that rules out any problems with the power supply. He tried a t-con, and got the same readings from the replacement. That leads me to believe that both are ok. I think it comes down to the main board or the master inverter.
            Im not sure what you mean. Why do you rule out the power supply? Recapping is the first thing you should do on a tv pre-2010. Whether it fixes it or not.

              Comment

              • lookimback
                Badcaps Legend
                • Aug 2013
                • 1489
                • USA
                #44
                Re: LG 42LG50 no backlight or display

                Originally posted by syaoran123
                Im not sure what you mean. Why do you rule out the power supply? Recapping is the first thing you should do on a tv pre-2010. Whether it fixes it or not.
                If you go back and read from the beginning, you'll see that he has all his voltages. He also got the backlights to turn on. I don't think it makes sense to spend money on something which isn't the problem. If he is able to fix it, maybe then it might make sense to recap it.
                ------------signature starts here------------


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                  • Daveleone
                    Badcaps Veteran
                    • Apr 2016
                    • 267
                    • USA
                    #45
                    Re: LG 42LG50 no backlight or display

                    Originally posted by lookimback
                    If you go back and read from the beginning, you'll see that he has all his voltages. He also got the backlights to turn on. I don't think it makes sense to spend money on something which isn't the problem. If he is able to fix it, maybe then it might make sense to recap it.
                    I agree. I think the power supply is ok. But wouldn't you surmise that the master inverter is ok if the backlights come on? Or could that still be defective?
                    I'm still going to exchange this new T-Con to see if I happened to get a defective replacement (which has happened to me before), but if that doesn't fix it then in my mind it was narrowed down to main board or panel.

                      Comment

                      • lookimback
                        Badcaps Legend
                        • Aug 2013
                        • 1489
                        • USA
                        #46
                        Re: LG 42LG50 no backlight or display

                        If you have the nearly the exact same voltage readings on the replacement Tcon, I think it probably isn't the problem. But, it's cheap enough that I'd probably try another one. The master inverter would be the last thing I'd try. I think that getting the backlights on, you should have had picture, but I don't know how that circuit affects the rest of the Tcon. I Don't think it's the panel, because you tried removing ribbon cables from the Tcon and still didn't get picture. I think it's going to be the main board. Did you look closely for cracked solder joints at all the connectors on the main board?
                        ------------signature starts here------------


                          Comment

                          • lookimback
                            Badcaps Legend
                            • Aug 2013
                            • 1489
                            • USA
                            #47
                            Re: LG 42LG50 no backlight or display

                            Also, check the solder joints at all the connectors on the power supply since the inverter circuits do run through it.
                            ------------signature starts here------------


                              Comment

                              • Daveleone
                                Badcaps Veteran
                                • Apr 2016
                                • 267
                                • USA
                                #48
                                Re: LG 42LG50 no backlight or display

                                I know it has been a long time, but I just wanted to follow up on this for closure in case someone else finds this thread in the future

                                The problem turned out to be the main board. I replaced that and all is well.

                                  Comment

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