Lg 50 inch no backlights

[tvtanner]

Help- i'm checking on lg 50ln5100 tv that has sound and picture that can be seen with flash light. All voltage seem to be correct. Voltage going to led backlights read 78 volts to two ckts. Am i correct in assuming that both ckts are open or what?

[sordids999]

Re: Lg 50 inch no backlights

Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

[tvtanner]

Re: Lg 50 inch no backlights

Does anyone know what the dc voltage should be for the backlights on a 50 inch tv. This one has 78 volts on two inputs to backlights. I read 78 volts on positive terminal of plug to lights and 12 volts on negative terminal. I can unplug output plug and then i read the 78 on positive and 0 on negative. Looks like back lights are conducting current to me. Any ideas? This set is about year and half old.

[budm]

Re: Lg 50 inch no backlights

Not until we see the pictures of both sides of the board to see how the LED strings are connected together (in series to form one LED string, or bunch of parallel strings), and the Voltage rating of the LED driver Voltage booster converter filter caps.

[Ltank]

Re: Lg 50 inch no backlights

I got one. Both channels to LEDs start at 110 vdc then drops to 78.5 vdc. My Fluke meter shows open both polarities on both channels. I too has picture when using a bright light on screen

[7thkey]

Re: Lg 50 inch no backlights

Do you the backlights light up for a moment when you turn on the TV? I am currently working on a similar issue with a 50ln5600 also just over a year old. My back lights run on 2 circuits. The first runs 1,5,6, in series the second runs 2,3,4 LED strings. On mine 2,3,4 are not lighting with the number 4 circuit not getting enough voltage. On my TV 1,5,6 all light up for a moment at start up. I have not done it yet but I am going to skip the connector board and hard wire them in the next couple days. The voltage on led + is 78 on both like yours.