Chosen Solution
I was given an LG 43UK6300 which has Audio & Backlight, but no video. The TV seems to turn on and off as expected and if i hit netflix button the white noise with no channels goes away and comes back if i hit the TV button. This tells me that the motherboard is working fine. Originally i didn’t see any damage to the TV, so i decided to bake the motherboard in case its a loose connection on the chip. Upon removing the unit, i noticed that one of the transistors is burnt. When i look back at the original pics, it was burnt as well. I have checked all the transistors legs to ground and i am getting 80 Ohm on the emitter and KOhm on the other two legs. For voltage, i have 13V on one of the legs and 10.5 on the other. Looks like the panel is not bad, but wondering if there is a way to confirm this. I could possibly buy a replacement board, but if somehow can find the transistor model #, i could solder it in too. How do i go about finding the part # for the transistor. Also is there anything else that i should check as well to ensure its not the panel.
To check if there is a problem with the panel, power on the TV (standby LED turns off) and measure LCD voltage on the 50V SMD capacitor by the #1 LVDS connector on mainboard. If with both LVDS flat cables plugged into the MB you get 0V, but with them plugged out of MB you get 29-30V, then there is a fault in the panel. Unfortunately LG sets made in 2018-2019 with BOE panels - at least on European market - develop fault(s) in panels. As per the service manual for 43UK6300PUE: for BOE panels, the mainboards (and panels) have 68 pin LVDS connectors, as opposed to 60 pins for LGD panels.
@arbitarytwist not sure about this “This tells me that the motherboard is working fine. “ with a busted transistor. There are no schematics for your main board so you would have to either replace the board or get someone with that same board to figure out that transistor.
