LG 42LE4500, Int No Backlights...

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  • Alastair E
    Chief Womble
    • Mar 2013
    • 1963
    • U.K.
    #21
    Re: LG 42LE4500, Int No Backlights...

    Hmm--without a signal driving the t-con/screen--From a Mainboard--you cant tell if its any good anyway!
    --lighting it up will tell you no more than glass-cleaner and a strong light/sunlight will!
    TELEFIX

    How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
    http://www.irf.com/technical-info/appnotes/an-1088.pdf
    PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

      Comment

      • citywidetvtech
        Member
        • Jun 2014
        • 14
        • United States
        #22
        Re: LG 42LE4500, Int No Backlights...

        not to dig up old posts. Put I put a 10k Resistor on pin 16 to ground and the backlights have been on all day so far.

          Comment

          • Greasejunky
            Member
            • Nov 2016
            • 14
            • Uk
            #23
            Re: LG 42LE4500, Int No Backlights...

            Originally posted by Alastair E
            Seems to be a common fault with these sets, Backlights failing after a few minutes, then after a while, 2 sec to black....

            Ive one of these sets, and have traced the fault to the LED Backlight Driver-board, which sits on the main PSU board--Its the small green one.....
            It appears the controller IC on that board is faulty.

            As a test--I pulled that green board off the PSU and checked to see if the main LED supply was still present--It was, although low at 79V

            For a larf, I rigged this low supply direct to the LED strings.

            The set works!--BUT has a dimmish lack-luster picture.....
            --IF I could now alter the feedback loop to get the voltage to 100V (The correct value) we be in business!
            Hi,

            Thanks for your informative posts on this issue.
            My 4500 is now doing the same and I too have narrowed this down to the ic. Now I'm not an electronics guru like many of you! I'm a lowly mechanic but I do enjoy fixing things and saving money!

            I read your post with interest on removing the driver board and running a feed directly to the LED strips. As the tv is in the bedroom I would be perfectly happy with the lower brightness caused by the voltage drop.

            Could you please give me some pointers on this so I can carry out this mod? Pictures would be perfect?

            I can solder fine and follow tracks and read voltages etc.

            Thanks very much

              Comment

              • Greasejunky
                Member
                • Nov 2016
                • 14
                • Uk
                #24
                Re: LG 42LE4500, Int No Backlights...

                Originally posted by citywidetvtech
                not to dig up old posts. Put I put a 10k Resistor on pin 16 to ground and the backlights have been on all day so far.
                Would like to know more about this if possible?

                  Comment

                  • vinceroger69
                    Badcaps Legend
                    • Mar 2012
                    • 6714
                    • uk
                    #25
                    Re: LG 42LE4500, Int No Backlights...

                    Originally posted by citywidetvtech
                    not to dig up old posts. Put I put a 10k Resistor on pin 16 to ground and the backlights have been on all day so far.
                    can you remember what ic this was on thanks
                    Last edited by vinceroger69; 11-28-2016, 10:19 AM.

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA
                        #26
                        Re: LG 42LE4500, Int No Backlights...

                        I wonder if City is referring to the pin 16 of the IC (which IC?) or pin 16 of the connector (which connector?).
                        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

                          • vinceroger69
                            Badcaps Legend
                            • Mar 2012
                            • 6714
                            • uk
                            #27
                            Re: LG 42LE4500, Int No Backlights...

                            Originally posted by budm
                            I wonder if City is referring to the pin 16 of the IC (which IC?) or pin 16 of the connector (which connector?).
                            yes thats what i was thinking too hopefully he may remember what he did and can up date the thread for us.

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA
                                #28
                                Re: LG 42LE4500, Int No Backlights...

                                https://www.badcaps.net/forum/showth...552#post705552
                                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

                                  • ReeceyBurger123
                                    Never Give Up !
                                    • May 2014
                                    • 7325
                                    • Britain
                                    #29
                                    Re: LG 42LE4500, Int No Backlights...

                                    Its not the Ics that fail. Something else on the driver goes bad but cant find out for the life of me what it is
                                    Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                                    https://www.facebook.com/Telford-Tel...7894576335359/

                                      Comment

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