How To Repair LED TV Backlight Problem – No Picture

By on January 3, 2017
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A customer of mine sent to me this BG LED TV with the complaint of have sound but no picture. This kind of problem usually caused by one of the bad backlight LED in the LED bar.




With just one bad LED, the TV will shut down thus no picture can be seen. Once the cover was opened I could see three circuit boards i.e; the power supply board, main board and T-con board see the photo below:

how-to-repair-led-tv

I then performed the dc voltage check on the LED backlight connector and found that the DC voltage came for a while and shut down. This usually indicates the LED backlight have problem. But I have to open the set in order to proof that I’m correct in saying one of the LED backlight could have problem.

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When you are removing the LED TV internal parts be extra careful for the Tab bonding. If you break it then the panel can consider useless unless if you know a way to fix it.

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Once the all the LEDs are exposed, you can check each of the LEDs with your meter by setting the meter to diode mode. A good LED should light up and the bad one will not light up. See the three photos below:

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True enough I found a bad LED. This is the main cause of the TV shut down. Since I have the LED bar and do not have the single LED thus I replaced the whole LED bar and can keep the remaining good  LEDs for future use.

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It was a fantastic view when you can see all the LEDs were perfectly lighted.

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Once you have confirmed the LEDs were all working fine and no longer shutdown, you can put back all the parts. Connect back the LVDS cables gently to the T-con board as shown below:

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The BG LED TV were finally repaired and I was very happy as I could earn some money from this work. If you truly want to venture into LCD or LED TV you can check out on Kent’s and Damon’s Ebooks. Once you have got their ebooks, you can ask for technical support from them to make you a good LCD/LED TV troubleshooter. All the best to you.

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suranga

This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.




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Note: You may check out previous post about fixing active speaker in the below link:

http://jestineyong.com/no-tuning-in-philips-tv-repaired/

 

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22 Comments

  1. Albert van Bemmelen

    January 3, 2017 at 11:21 pm

    Thank you Mr.Suranga. Very professional repair with clear photos and explanation. Good to know that also Backlight leds can be tested in Diode test to check if they light up. Maybe that is also a good reason never to test CMOS ICs with a Digital Meter in Diode/Beep test. And good to know that the reason a LCD TV quits can be caused by a single defective Backlight Led.

    Likes(7)Dislikes(0)
    • suranga Electronics

      January 5, 2017 at 2:05 pm

      Hi Mr- Albert van,

      Thanks So Much for Your Comment,

      Likes(0)Dislikes(0)
    • Jack rogers

      April 5, 2017 at 9:01 am

      Could you indicate how much the repair cost? I had the same problem. . Took tv to repair shop they said it would cost more to repair than what the tv was worth $6-700 i was suspicious when they said they would keep it and dispose of it as it was worthless Thanks

      I

      Likes(0)Dislikes(0)
  2. Parasuraman S

    January 3, 2017 at 11:53 pm

    Very useful service info! I have never ventured to open up an LED TV to this extent! Now, I think I can give it a try! Many thanks!

    Likes(3)Dislikes(0)
    • suranga Electronics

      January 5, 2017 at 2:06 pm

      Hi Mr,Parasuraman

      Ok ok

      Thanks You..!

      Likes(0)Dislikes(0)
  3. Bulent NUR

    January 4, 2017 at 1:03 am

    Thanks for sharing, good job.

    Likes(3)Dislikes(0)
  4. Randy

    January 4, 2017 at 1:51 am

    Nice job! But I am somewhat confused by your sentence that you were happy to earn some money from this repair, do you not get paid for the electronics work you do? You have valuable knowledge and skills and should be well paid for your work, I have seen it many times here!

    Likes(1)Dislikes(0)
    • suranga Electronics

      January 5, 2017 at 2:08 pm

      Thanks Mr- Randy.

      Likes(0)Dislikes(0)
  5. Anthony

    January 4, 2017 at 2:40 am

    Good repair Suranga and it was fortunate that you had the exact same
    LED strip that you could use in that tv. Thanks for sharing your articles
    here. Kind Regards

    Likes(1)Dislikes(0)
  6. zaheedi farjan

    January 4, 2017 at 2:40 am

    Great awesome i have learn more thank u sir i have a question i got lately a 32 inch sony bravia the prob is the image is blurred n
    negative no colour plse advise me
    Regards
    Zaheedi farjan

    Likes(1)Dislikes(0)
  7. mahmoud_tajpour

    January 4, 2017 at 2:47 am

    Hello Bandara really well done.

    Likes(1)Dislikes(0)
  8. Mark

    January 4, 2017 at 5:59 am

    Hey Suranga,
    Thanks for your article. I have dealt with similar cases recently in the automotive field, where faults will make the vehicle either shut down or go into 'limp home' mode - a limited system of operation. These were designed to stop over-current of the system and protect the Electronic Control Unit. I guess it is similar with the TV - a protection mode is created.
    Well done on your repair.

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  9. angelo

    January 4, 2017 at 6:40 am

    great job sir Suranga

    congratz

    keep it up....

    Likes(1)Dislikes(0)
  10. Pravin Mevada

    January 4, 2017 at 8:09 am

    now some led for back light 6 volt which not glow with diode test I suggest test led tester is best for single or hole back light Thanks,

    Likes(2)Dislikes(0)
  11. Robert Calk

    January 4, 2017 at 12:07 pm

    Thanks Suranga. Nice work.

    Likes(2)Dislikes(0)
  12. Yogesh Panchal

    January 4, 2017 at 3:03 pm

    Suranga, Good job! keep up Sharing.

    Likes(1)Dislikes(0)
  13. Tito Kanshulu

    January 4, 2017 at 4:40 pm

    Good work Suranga.

    Likes(1)Dislikes(0)
  14. Humberto

    January 14, 2017 at 12:11 am

    Suranga, great repair and very good explanations.

    Likes(0)Dislikes(0)
  15. Chris

    January 22, 2017 at 10:07 pm

    Hi Mr.Suranga, you are a very high skilled service person in the field of
    audio and tv repairing.
    You share also very interesting information's with as and that are very valuable for persons who deals with such repairing as you do.
    I can say, hats of and look forward with the upcoming modern technology.
    Be between the best pros as you like now too.
    My best regards.

    Likes(0)Dislikes(0)
  16. CAIN

    February 7, 2017 at 7:25 pm

    FANTASTIC VERY INTERESTING INDEED I ENJOYED IT AND ALREADY REPAIRED MORE THAN 10 LEDS AND MADE SOME MONEY MY CHALLENGE IS TO GET THE SPARES HEREB ZIMBABWE

    REGARDS

    CAIN

    Likes(0)Dislikes(1)
  17. Samsudeen

    February 20, 2017 at 11:50 am

    Dear sir
    Every time you give useful information to improve the knowledge about electronics.I am really thanks to you.

    Likes(0)Dislikes(0)
  18. reza

    April 12, 2017 at 1:15 pm

    hi
    thank u

    Likes(0)Dislikes(0)

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