One Side Dark Problem Solved In Samsung Back Screwless LED TV Model UA43NU7100K
This TV was brought by a new customer through one of my friends with the complaint that one side of the screen was dark. Such problem can be created by either one side backlight failure or side Cof bonding issue. When I consulted my techie friends sharing the video, they told me that this TV did not have a side buffer or side Cof and it was a failure of one of the two edge LED TV strips and further it was a common problem in this type of Samsung TVs.
So, I accepted the TV and in order to open the screw less back, I ordered for special openers and followed the guidance given in the following video here (link sent by my techie friends):
Then opened the back cover of such a TV with a lot adrenaline pumped up within, as it was a maiden attempt! It had a lot of cobweb and dust, which I cleaned using my Cordless Vacuum Cleaner. Then took the back cover to outside and used my special brushes to clean it.
To locate the back light, we need to dismantle the TV fully. So, I removed the speakers, the scaler board protecting metal cover and disconnected the ribbon cables from mother board to panel and slowly detached the front frame, under which the panel is seated, then slowly and carefully, lifted the COFs along with the two scaler board and taped it onto the front side of the panel. Then used a thin plastic film to detached the panel from its seat on all four sides. Then inserted a large size thin Mica Sheet and lifted the panel carefully not to cause a caving in and break. I did all that on my son’s bed as he was conveniently out of town. Then removed the various sheets under it like diffuser, reflector etc. after removing the panel bed frame. Finally located the two strips of edge LED TVs stuck at the bottom of the frame.
I used my LED backlight tester and found that the strip on one side was totally dead. Then peeled of the two strips and carried it with me to the market for fetching a replacement. When we replace the strips, we should not replace only the defective one, we should necessarily replace both in order to have a matching current drawing.
Otherwise either the LED drive or the other strip would blow. As it was not available I placed an order with the regular supplier situated in another town (around 60 KMs from my house) and got the exact replacement the next day. I scraped the gum and removed the remnants of the backlight sticker and cleaned that area thoroughly using IPA.
Then used a double sided thin tape of same width of the LED strip and fixed it on the backside of the new strips. Then aligned the strip properly in straight line and stuck it in place like how it was before. Then inserted the connectors checking whether the positive and negative sides were in correct position. As the back light of Samsung TVs would switch on automatically without a need to connect it to the Mother Board, I applied power and was glad to see the LED strips glowing brightly. I checked the voltage and found it to be around 170V. Since one strip had 28 LEDs in it, which are presumably 6V LEDs, the voltage seemed to be alright.
Then I put back the sheets, its holding frame etc. one after another and carefully placed the panel and ensured that it was seated properly on all four sides, especially the corners and fixed the front frame on top of it and snapped it in properly, by applying gentle pressure. To tell you frankly, every technician who has to do this type of dismantling and reassembling would undergo some amount of mental pressure as the panels are very brittle and even the slightest loss of focus and care would result in its breakage or developing cracks. Then fixed the two scalar boards in its place using the clip locks provided.
Then the metal cover and then the two stand-fixing metal frames on top it at each ends. (The fourth picture given in the beginning has all fittings in place and you can zoom in to view). Then applied power and I was glad to see full display without any signs of strains or breakage to the panel. So, pressed down the back cover in its place and fixed the stands and allowed the TV to run for several hours before informing the customer to come and collect. As the video format in the USB, where I play my favourite Sherlock Holms movies, was not supported by this TV, I had no other go but to play some music from a different USB. Anyhow, mission accomplished with a lot of vigor recharging experienced. Satisfaction with additional qualification entered into its collection bag with the deserving priority assigned.
This article was prepared for you by Parasuraman Subramanian from India. He is 74 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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Waleed Rishmawi
December 7, 2024 at 4:11 pm
I have encourtered this kind of TV in my shop a few months ago and and sad to say opening the back cover was a little bit hard so when you said screwless it brought back a few bad meories but I am glad it was up and running in your case. thanks for sharin and have a blessed day
Parasuraman S
December 7, 2024 at 7:43 pm
Many thanks dear for your encouraging comments, dear friend!
Albert van Bemmelen
December 7, 2024 at 4:56 pm
Astonishing that you placed an order with the regular supplier situated in another town and you already got the exact replacement the next day! Something so fast would be unthinkable in my town or country.
And this repair is another example that shows only the most experienced engineers dare to do such risky tasks successfully without much hesitation!
Parasuraman S
December 7, 2024 at 7:45 pm
Many thanks, dear Albert for your encouraging comments after keen observation! In our country, we have good courier services and it would reach us soon.
Mark
December 7, 2024 at 5:58 pm
Well done Parasuraman!
I had a similar fault with a LG TV that gave me quite a headache. It would work for 20 minutes only.
I will have a video and article out soon.
Great job getting the back off. Requires a lot of patience!
Parasuraman S
December 7, 2024 at 7:46 pm
I am eager to read that article and await to receive it soon! Many thanks for your continued support, dear Mark!
Mark J
December 8, 2024 at 4:36 am
Parasuraman great job on the repair.
Parasuraman S
December 8, 2024 at 10:50 am
Many thanks, dear Mark!
Yogesh Panchal
December 8, 2024 at 4:07 pm
Good Job! Sir,
i think the process is same as Opening computer LED/LCD Monitor?? they also having plastic frame locking .
Parasuraman S
December 8, 2024 at 5:00 pm
This is not a plastic frame locking. This TV gets locked on springs that of straight wires onto the rear cover which has hooks to remain locked by the tension of the spring. Thanks, Yogesh Bai!
Imoudu.O
December 9, 2024 at 4:26 am
How i wish to watch a video of opening such a tv back cover.Thanks for sharing sir.
Parasuraman S
December 9, 2024 at 7:05 pm
Yes, it is a rare chance. Thanks, dear Imoudu!
Tito Kanshulu
December 13, 2024 at 2:16 pm
Well done and good repair article Parasuraman.
Parasuraman S
December 13, 2024 at 5:07 pm
Thanks, dear Tito Kanshulu!