LG 55UH6150- trouble powering up, then half lit screen (pictures!)

[valvashon]

The 55" LG has been in the basement for a few months without being used. Turned it on yesterday, set came on as it should and showed a complete screen for about 5 seconds (was on a broadcast channel but no antenna was connected), then the screen went mostly dark with about 1/3 of the screen on the right lighting up with brighter lines in that lit part (sorry, no pictures of that). Power LED was cycling too, preventing the TV from fully powering up.
Pulled the back off, all boards looked OK. Pulled the LED connector, turned the set on to see if it would power up but I don't belive it did. I then plugged the LED's in and powered it back up. Heard a bit of a snap and then the TV finished powering up but now with the entire right half dark and the left half lit up.


I'm probably looking at LED replacement of course, any ideas how difficult it is on these? Are there LED's on the top and bottom like there was in the CCFL days? Are the LG sets all glued and bonded together or are they serviceable? I can pull it apart again to take pictures of the boards or anything else if it would be helpful.

[valvashon]

I did find an "iFixit" for this but it's light on the details. What voltage should I look for at the LED driver connector to make sure it's the LED's and not the board?

[Davi.p]

How was in this period the climate in that basement? Humidity? Was it well covered? The wiser action you can do, since at first power up the behavior was different, is to wait for eventual humidity residue to evaporate, then if in a 3-4 days i does not fixes itself think about opening it and watch for the bars codes (left is one code, right is another)

[valvashon]

Finally got around to getting some new LED strips for this TV. I've only worked on relatively small screens so far (24" and smaller) so I found this size of TV a little intimidating as I was sure it would be much easier to break the screen given the sheer size. I pulled the back cover off, then removed the speakers and the power button assembly. I then removed the metal frame from the TV (there are many small Philips head screws to remove) and laid the TV back down using painters tape to hold the glass in place at several places and the corners. This has to be done as at this point the glass could fall out as the metal frame has been removed.

Then I pulled the two bottom metal covers off and unclipped the LCD driver boards from the white ribbon cables in the middle, seen above. I then folded the driver boards (one long one on each side) out and laid them flat on the bench/desk "below" the TV.


Struggling with how to get such a large screen out without breaking it or mixing up the diffuser sheets, I came up with this- unclip the plastic frame from the metal rear and lift the metal rear part up and off of the screen which will be left safely on the work bench. To do this I unclipped all the plastic clips and at the corners, use a couple of spudgers/picks and on one corner, a very small screwdriver was needed to lever up the metal rear from the frame. Do not stick the screwdriver in the corner, use the plastic frame as the fulcrum and push the screwdriver against the metal back; the friction should allow you to lift up the metal back. Sticking the screwdriver in the corner opens up the possibility of breaking the glass. Once I had a corner up I put in a screw that was holding the metal frame to hold the back up and prevent it from settling back down and re-clipping.



I then put some long 6MM screws into the VESA mounts to use as lifting knobs. With a helper I slowly lifted the metal back off of the plastic frame/screen assembly. Do this slowly so as not to disturb the diffuser sheets as some suction will be created as you lift. The screen assembly will be safely left on the work bench.



I reattached the power button assembly (temporarily) and re-applied power. First picture is of the one remaining good strip, second picture is a new strip plugged in temporarily to make sure the strip was the problem. It was and there was visibly burnt traces on the bad LED strip. Notice the color temperature difference between the two strips. I replaced both of course for this reason and because as long as I'm in there. New ones were $26 on fleaBay.



Visibly burnt out LED on left, two new strips installed on right.



I used a box cutter to remove the old strips and some alcohol to clean up any remaining adhesive. Be careful when putting the new ones on, the adhesive is very grabby. Second picture is of the installed strips.





Here's what the screen assembly looks like sitting face down on the bench. After installing the strips, this is what you will be putting the metal rear portion back on to this. Remove your 4 holder screws at the corner and gently clip it all back into place. Gently tilt the TV up supporting the taped glass screen and lay the TV on it's back (remove the 6mm "knobs" first) and re-install the metal frame with all the Philips screws. Put the TV back down and reassemble the screen driver boards, power button assembly, speakers and rear cover.



And here it is with 100% of the screen lit up again! Well worth the time to do this even though the TV dates from 2016. It's still a smart TV and has a great picture and a pretty good OTA tuner too.

Val