Masking At Panel Side Of LVDS Solved No Display Sound Ok Problem In LG LED TV Model 43UM7300PTA
I picked up this TV from a customer’s home after checking the complaint of no display, but sound ok. Opened the TV and subjected it to a thorough cleaning. Let us have a look of the inside:
Whenever we get such a complaint on a TV which has two LVDS cables going to each sides, the best way is to remove one of them and check what happens.
So, I removed the left one that you see at the bottom with a red label on it in the above picture. Look at what happened to the display:
The display came on with white light on left side and black on the right side. It was dark when both the cables were in place. I just touched the LVDS cable that was taken out, upon which lines were seen on the right side, indicating that that side was ok. I re-inserted the left cable and pulled the other right one. Then there was complete dark display. So, I re-inserted that too. The next step was to mask pins beginning from one side of the connector.
We need to mask one or two at a time and proceed up to around 10 or 12 to get the result. This is a time consuming job as we need to place a mask under the connector exactly on the spot, then switch on TV and check whether display has come or not. If not, we have to remove the connector, extend the mask for one or two more and keep trying. Finally when I masked ten pins, the display came on. Let us have a look at a connector (not the one I masked) where the position is marked.
I have also given a picture of masking done on the other side connector, which is the second one above. In the third picture above, you can see the connector under which the masking was done on the right side. These tricks might not work in every TV.
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In certain TVs, we may have to remove the resistors at the far end of the scaler board one by one and check, which is really a pain because of the very tiny components. Anyhow, the display came on very well though there were a few lines at the bottom of the panel, which did not hinder view. Let us have a look:
What did we do here? We cut the lines to the portion of the panel, which were internally short. Whenever, an internal short is sensed, the TV would shut down the display. By doing this masking, we circumvent the problem or rather fooled the system! I fixed the back cover. Well, I forgot to mention that opening the back cover of this type of LG TV is not that easy. After removing the screws, we have to press the centre of the back cover with our elbow on one side and pull up the cover from the bottom side. Kindly watch the following video, which was provided by my techie friends as I could not take out the back cover after removing the screws.
The language is Hindi, but we can watch what he does.
Mission accomplished and I tested the TV for several hours before giving delivery to the customer’s house.
While satisfaction was of course obtained in completion of the work, the method used was certainly not to my liking!
Nevertheless the collection bag accepted it!
This article was prepared for you by Parasuraman Subramanian from India. He is 76 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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You may check on his previous article on Scaler Board Replacement In Samsung LED TV Model UA32EH4800R
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Albert van Bemmelen
February 7, 2026 at 5:18 pm
As usual another professionally done majestical like bypass on the LVDS connector lines to the LCD panel to escape the tv's power on over-current protection!
Parasuraman S
February 7, 2026 at 7:22 pm
Many thanks for your expert comments, dear Albert!
Yogesh Panchal
February 7, 2026 at 5:41 pm
Good Job! Sir
Now companies making the product hard to repair by outside technicians.
Parasuraman S
February 7, 2026 at 7:23 pm
Yes, a type of monopoly! Many thanks for your comments, dear Yogesh Bai!
Herb
February 7, 2026 at 9:44 pm
Greetings to India. You always do a very good work. The funny part: I live in Austria and the last picture you show on the repaired TV is 10 km away from me. Its a place called Hallstatt. A big surprise for me 🙂
Parasuraman S
February 8, 2026 at 8:16 am
Birds of the same feather flock together, the old adage goes! It is always like that! Many thanks for your comments! My pleasure and fortune to know you through this wonderful forum!
Mark J
February 8, 2026 at 4:12 am
Parasuraman great article very informative. Thanks again for sharing these.
Parasuraman S
February 8, 2026 at 8:16 am
Many, many thanks, my dear Mark!
MP
February 8, 2026 at 5:19 am
Good repair lesson. Anyway, I find this a maze of explanation; ..... masking done on the othe side connector. Should I take it to mean, on the other side of the conector in question ?
Parasuraman S
February 8, 2026 at 8:23 am
Yes, dear MP! Many thanks for your keen observation and comments!
Jim
February 8, 2026 at 2:28 pm
Great tip! .. I have seen this several times on Toshiba lcd/led hdtv’s in the late 2000’s
Parasuraman S
February 8, 2026 at 6:07 pm
Many thanks for your comments and sharing the experiences!