LG 49UF6400 UHD 4K TV Picture Turned Blue. Let's find out why.



A phenomenon that happens to all LEDs when they are over driven.
Heat and strong blue light bleaches the yellow phosphor that makes a white LED appear white. When the phosphor fails, the LEDs turn blue.
Here is an example on a 3 year old 4k LG television. This type of faliure can be prevented by turning down the backlight to a reasonable level, but unfortunately most people use them how they come out of the box, cranked to full, and this is the result.

31 Replies to “LG 49UF6400 UHD 4K TV Picture Turned Blue. Let's find out why.”

  1. Tre Douglas

    I have the same TV, bought it 3 years ago and even with the backlight at 60%, i'm now starting to get the blue tint. A bit bummed about it, although this video does an awesome job explaining the likely reason behind it. Any recommendations on good 4k TVs that are more efficient and last longer? (from your opinion)

  2. Tom

    Thanks for this vid, I have the same model LG and the blue tint just started in the last two weeks and has been getting worse daily. It’s only 3 years old and I’ve been learning its such a garbage product.

  3. James Reader

    Hi, can a faulty power supply cause this? My LG has started going all blue in places only had it 2 year, always looks worse on camera but on a white background they really stand out. Also is there any tv make you would recommend? Was thinking about getting a sony next as i cant see as many complaints as samsung and lg.

  4. d0Bored0b

    Head's up, it only takes about $50 for the LED array replacements and about 2 hours of unscrewing and removing the screen to have this TV looking like new again. It's more than economical (especially on a $400 LED TV that someone received for free).

  5. Dood1es

    I had the same problem with a UF series LG that is just over 3 years old and have seen this same blue tint issue on a number of LG's on display at Target and Walmart. Sure they are on many hours a day, but it doesn't seem to happen to the other brands displayed next to them. I am thinking there should be a class action suit to address this problem.

  6. AJ Gibson

    Bought my LG TV and it only lasted about 3 or 4 years as well.. at this point I think although these newer TVs look good they suck! Today they make everything cheap and sell for high prices. electronics cars and even houses back in the day were built with more durability and pride. At 500 700 1000 dollars you wouldn't expect your TV to only last until the warrenty runs out. Then for a technician to say it's cheaper to buy a new TV? What a ril off might as well buy a projector at least you can change the lamp its small dont take up much room other then when watching it on your wall at 32" or 200" think I'll try that route or buy an old CRT TV these new ones suck!

  7. Allen Fleckney

    Hi , I’m guessing the customer did not want further investigation on this one ? We have just had the same tv with the same issue in my workshop innthe UK. On this one all of the LEDs had turned blue. It’s what some do when they are failing apparently, even though I’ve never heard of it before. Not an expensive fix. I have photos if you want to see. Cheers.

  8. mrnmrn1

    @12voltvids If you change the LED strips, it is well worth to change the current monitoring resistors in the LED driver supply, to reduce the maximal current by at least 20%, but better by 25-30%. They're driving the hell out of the LEDs. A relative had an older (2014 model I think) LG TV, which just lasted over the 2 years warranty period. Many LEDs were literally burnt, 4 or 5 of them so heavily that the diffusor lens are completely molten, and in one place, a hole burnt into the LED strip PCB.

    That was the point where the circuit finally opened, and the backlight stopped working. I replaced the LEDs on the strips (as new strips cost too much), and bought a second hand dead strip to replace the molten lenses. I even soldered 4.7V (or 4.3?, 3.9? I don't remember…) 1.3W Zener diodes across every single LED, so if one (or even a dozen) LED opens, the circuit is still complete and the set continues to work, to the point where the majority of the LEDs die, then it will be very dull, or the LED supply finally triggers its protection, because the Zener voltage is slightly higher than the normal LED voltage, to prevent the Zeners stealing power during normal operation.

    The backlight is a bit uneven, because some of the diffusor lenses are not perfectly aligned. I had to crack the glued joints between the PCB and the lens, and in a lot of cases, the glue was stronger than the spacer leg on the lens, and the spacer cracked from the lens. When I realised this, I started to mark every lens to the PCB with numbers, so I know the original position of every lens. The stips handled this way, produce even backlight, only the first strips I rebuilt without marking the lens produce uneven light (and where I had to replace the original lens).

  9. Dave Turner

    Purchased a Panasonic Viera TX-26LMD70A 9 or 10 years ago. Still works fine. Unfortunately my eyes are fading and I'm going to need a bigger TV in order view it from a sensible distance, 10ft (3 metres).
    Loads of research required to pick a good 'un.

  10. Walt's Channel

    Totally agree with you on the difference between plasma, LCD, LED. The refresh rate on plasma sets is so much better than anything else. I got mine 10 years ago as well, and I'll hang onto it as long as I can. I don't care about power consumption because it's only on 1 – 3 hours a day.

  11. James

    I have two Panasonic plasmas one is standard def 15 years old and the other one is HD & 7 years old. Both still have great perfectly bright pictures, they've done a lot of hours. The gym I go to bought eight Samsung LED back lit TVs about 18 months ago they are now all completely shagged. Ok they've been on 15 hours a day, but they all totally buggered. The back lights have virtually all gone and they barely have a picture on them, I don't know why they don't just switch them off. One has no back lights at all. That is just crap, pieces of garbage. Samsung should be ashamed of themselves.

  12. butchtropic

    Wow, great info here, I've got an '08 "47 Phillips that of course uses fluorescent backlighting, it does not have that many hours on it, but the screen is still perfect. Now that I know the crap life expectancy of these LED's I'm going to reduce the white level on the 2 of those that I do own and not let them just run on when not being actually watched.

  13. paul collins

    I have a Plasma and love it,I don't care about the energy consumption, mine is a Panasonic, you could cut yourself with the sharpness of the picture, the LED upstairs I just don't bother with Crap.
    I loved the video.
    Paul

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