We haven't had a TV in over 5 years now. Just haven't felt the need for it, and it ended up sucking up too much time. But, my father in law recently found a 47" LG in a dumpster. He took it home and it didn't work, so my wife asked if I could try to fix it.
So, I plugged it in, the screen blipped with brightness for a second, then went off. I then went to google and typed '47LN5400 fix'. The first youtube video showed the exact same problem I had. The screen blipped with brightness and then went black. He goes through the TV and finds out that one of the LEDs is shorted out from overheating. So, I went on ebay and found a new LED kit to replace them all for $26 shipped.
Fast forward a week and this is what I did:
Flip the TV on its face and take out all the rear cover screws.
Unplug the controller receiver board.
Uncover and remove these ribbon cables going to the LCD screen.
Remove the front bezel.
Remove the metal trim pieces holding the LCD screen to the frame.
Pull off the LCD panel very carefully. Remove another bezel / frame piece. Remove the light diffuser.
This gets you to the light box. The white insert also comes out after unclipping those white spiky things.
Then you have the LED strips that actually light up your TV.
The kit I got had new strips in it, so I hooked those up for testing purposes and sure enough, they all lit up after powering the TV on. So, the old strips get pried out, and the new ones are stuck down with the included double sided tape. Then its just reverse for reassembly.
Thats all you have to do to fix up a TV with a burnt out LED. I do find it very dumb that the OEMs drive their LEDs hard enough to burn them out. This should never happen. Add another few LEDs in there. This model TV is at most from 2013. There is no reason for it to have failed in 6 years. Thankfully the fix was easy and it found its way into someone hands who could fix it.
I'm still debating keeping it. Its on probation right now. If it starts sucking up too much time I'll give it away to someone.
