Replacing Backlight In A Frameless LED TV Is A Complex Work – IMPEX MODEL 50UFX2AC11
This TV belonged to one of our family friends who runs a grocery-vegetable-bakery shop (I am purposefully avoiding the use of ‘cum’(LOL) opposite to my house. The complaint mentioned by his daughter while bringing the TV in was that there was sound but no picture. I powered the TV in front of them and tapped the panel gently to know whether the backlight was there. It was missing. I told her that the backlight probably has conked off and I may have to dismantle the whole TV to replace it.
Further mentioned that if there was any problem to the panel which cannot be ascertained without the backlight, I cannot be held responsible. Having made my terms very clear, whether the customer is known, close or not, I opened the back cover when I got free to see how the condition was. I could make out that the TV had been opened before as the tamper proof sticker on the screws was torn.
Removed the backlight connector and used my LED tester and found that it was dead. Then the laborious work of removing the panel commenced!
This was a frameless panel TV, which means there won’t be any frame holding the panel on all four sides. There will only be a protective cover at the bottom. The panel would be stuck to the supporting back frame on all the sides. In some TVs, I heard from the group that there would be hidden hinges and screws on the sides on some panels! Anyhow, I removed the LVDS cables from both the scalar boards, peeled off cotton tapes from the bottom frame, located underneath the 12 COFs, removed 7 screws and took out the bottom holding frame. Then peeled the scalar boards gently from tapes and ground tapes and allowed it to hang loose. Then turned the TV over and kept it facing up. For all these works, I used my son’s bed as he was not in town! Then inserted a thin plastic sheet (the one you get whenever a mobile glass is changed) under the panel beginning from the left bottom. In this TV, the bottom portion was not stuck.
It was free. Then slowly took it to the sides, and detached the panel from its sticker progressively moving the plastic slowly, firmly and steadily but without applying any force. After going around and reaching the left side corner, I took the plastic sheet on reverse so as to ensure that the panel was indeed free. Folded the scalar boards onto the face of the panel and stuck it with tape to prevent these getting strained and damaged. Inserted a sponge like thermocol sheet under the panel slowly and held it balanced very well and moved it out.
Detached the rectangular frame under which the reflector, diffusor sheets were held. We need to gently release the frame from all the locks around and lift it. Put an identification mark at the bottom right corner on each sheet with numbers and moved it out. The backlight reflector was also stuck with double sided tapes and I really struggled to remove it without causing any tear. There were holding brackets and screws as well. Peeled off the backlights one by one. There were four strips with 12 LEDs on each.
Took the backlights with me during my visit to the hospital next day to fetch exact replacement. Got it from the regular shop which I brought on my return from the hospital in the afternoon. Then continued my work as a post-lunch operation. Placed the LED strips on the appropriate places, marked the place with a sketch pen so as to stick double sided tapes on the bottom frame. Placed the strips on top of the stickers and pressed it down very well for a proper bond. This is necessary to dissipate the heat to the metal bottom. Completed this work and connected the wires as how it was before:
Applied power and saw that the backlight was working very well. Replaced the reflector sheet once again pressing it down on its left over stickers and fixed the spacers and screws. Elevation brackets (spacers) are those protruding plastic pieces that hold the top sheets in place to prevent heaving and bending in.
Placed the diffusor sheets on top of it and fixed the rectangular frame and snapped it in its holdings. Then I remembered that I had to remove the old stickers of the panel from this frame. Though I tried to scrape it off using a pen knife, it did not come out well. I could not apply IPA as it would spill on to the sheets and make marks on it. The diffuser sheets are all coated with something and any attempt to clean it would also cause marks. We should be very careful in handling the sheets. So, removed the frame and applied IPA and peeled it off from all sides:
Cleaned the slot provided for sticking the tape and made sure that the fresh sticker will stick well. The width of the tape used for this is very less and let us have a look at the full roll. 3/4th of the roll had to be used on all three sides:
Stuck the new tape on all the three sides and pressed it down firmly, aligning it well to fit in the groove properly. I did not peel the protective sheet from the top of the double sided tape at this stage, but only lifted it at one corner so as to pull it out after placing the panel. Checked and ensured that the bed for the panel is even and there are no protruding hindrances that could cause damage to the panel immediately or later due to strain. Cleaned the edges of the panel on all sides so as to have a proper bonding with the new sticker. Placed the panel on top, aligned it well with the frame and peeled off the red protective sheet from the sides and gently pressed all the three sides to enable a firm bonding. Released the scalar boards and allowed it to hang freely on the bottom side.
Stuck fresh cotton tapes under the COFs like how it was before.
Put transparent tapes diagonally at two top corners of the panel in order to ensure that the panel did not lift out when the TV is turned face down to finish work on the PCB side. I also put two tapes in the centre on both sides. Kept the TV facing down and inserted the scalar boards into its rubber brackets and re-inserted the LVDs cables. Put back the peeled off the grounding tapes in the appropriate places. Applied power and saw that there was no problem and the Impex emblem showed up correctly.
Switched the TV off and fixed the bottom cover and fixed the seven screws once again. Fixed the speaker cases which had the control and IR Board in it and fixed the connectors back to the Mother Board. Connected the speakers also once again. Routed all these wires properly to avoid getting wedged when the rear cover is fixed. Kept the TV on my sons’s bed and played my favourite testing movie from the USB. You can see the pictures and judge yourself:
I allowed the TV to be tested for several hours before fixing the back cover and informing the customer to come and pick it up. The sweat forming laborious work finally came to an end bringing a big relief for me because of which the satisfaction was more than happy to jump into the collection bag on its own! Does the customer realize how difficult it is to replace a backlight in this type of TVs, especially when it is very large? I don’t think so!
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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Yogesh Panchal
November 29, 2025 at 5:02 pm
Sir,
Congratulations! for successfully treated the Patient. as found this is vary complicated case & chances are high to get patient demise while operating because of COF & thin Display screen,it is always helpful to us to make operation terms,Possibility of damage very clear to the customer and to take his acknowledgement prior to repair attempt.
Parasuraman S
November 30, 2025 at 12:38 am
Ha! HA! Very true! These are calculated risks, especially at my age! Many thanks for your involved comments, dear Yogesh Bai!
Albert van Bemmelen
November 29, 2025 at 6:28 pm
The article may be of great help when I will have the time to start fixing my brother's large 50 inch Samsung TV that now has a lot of domes that fell off from the backlight leds. Causing many bright suns in the TV screen picture.
I already bought a quite expensive panel sucker lifting frame from Aliexpress to avoid breaking the thin glass screen plate when lifting it off to be able to reach the led backlight strips. And transparant UV hardened glue to re-attach the diffuser domes back on.
Your warning to put an identification mark at the bottom right corner on each sheet with numbers before moving them out is a good tip. With also the warning tip not to use any cleaning fluid on the diffuser sheets that are all coated with something that would leave stains. The text where you mentioned that you had to remove the old stickers of the panel from this frame that did not come out well where you used a pen knife was however not clear to me yet. Not exactly seeing where those stickers where placed.
Parasuraman S
November 30, 2025 at 12:44 am
Glad to find that it was useful. What I meant was the remanent of the double-sided sticker tapes. Many thanks for your expert comments, dear Albert!
Mark J
November 30, 2025 at 5:11 am
Parasuraman good article very helpful. Thank you for sharing these Tv repair arctilces.
Parasuraman S
November 30, 2025 at 9:48 am
Many thanks, dear Mark!
Imoud.O
December 1, 2025 at 4:59 am
I,ve learned new skills from this acticle,I really appreciate you sir,thanks.
Parasuraman S
December 1, 2025 at 12:57 pm
Glad that the article was found useful to you! Many thanks, dear Imoud!
Philip
December 2, 2025 at 6:54 pm
Well explained repair, a repair that must have taken at least a good 2 straight days. When I come to think of it, I almost feel the back ache of prolonged bending, unless I'm working on something placed at table-level (two and a half feet off the floor) while I'm seated on a chair (one and a half feet above the floor). I presume the lights were not killed by one cause or another, maybe just a natural death and as such there was not much need for a preventative measure during replacement. It matters little what hardship a repairer undergoes, thats immaterial to most customers. All they want to see is a repair completed. They may even blame a repairer when ordered spare parts delay to arrive. Determination keeps hope alive as despair sets in. A successful hard repair like TV screen light restoration afterall has a way of melting hearts with overwhelming joy ! In our hearts when gloom meets joy, gloom always paves the way for joy, what else can be so pleasing ?
Parasuraman S
December 2, 2025 at 10:46 pm
Very involved and experienced comments! Many thanks for your support!