Mr Light Needed A Backlight Fix
This LED TV belonged to my colleague in the Hospital and the complaint was that it had sound but no display. Though this could be due to many reasons, I guessed it was a case of backlight problem. I opened the rear cover and here are the pictures:
When I powered it on and checked, I noticed that all power supplies were ok. There indeed was the voltage required for the backlight; but the output was more as there was no load. I used a backlight tester and tested the backlight and found it to be dead confirming my suspicion that this Mr.Light LED TV had its backlight conked out!
I removed the front and side covers, removed the panel and reached the backlight underneath the panel. Removed the backlights and ordered for a similar set. Fixed the new backlights in its place when replacements were received:
As advised by my technician friend, who owned a spare parts shop and sent me the replacement, I replaced the electrolytic capacitors on the board, including the inverter section.
This had a combo-board (an all-in-one board).
Then when I re-fixed the panel and tried, the picture was back on. I let it run for a few hours before fixing the back cover.
Here is a picture of the outcome:
Here is the picture of the caps replaced:
Another mission accomplished and satisfaction earned by the collection bag!
This article was prepared for you by Parasuraman Subramanian from India. He is 72 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
January 21, 2022 at 10:04 pm
Good Fix! Sir
Parasuraman S
January 21, 2022 at 11:38 pm
Thanks, dear!
Mathew Charles Karonga
January 21, 2022 at 11:05 pm
Thank you for deatailed step by step and sequential repair.
knowledge is power ,knowlege solves our problems.
Parasuraman S
January 23, 2022 at 12:41 pm
Many thanks for your supporting comments!
Tayo
January 22, 2022 at 3:34 am
You always make repairs look so easy. Well done. Its not common for multiple LED strips to spontaneously go dead. A few LEDs will go out one by one. Or you get a short which takes out the individual strip. Any idea whay happened in this case?
Parasuraman S
January 22, 2022 at 9:46 am
Only a few LEDs had gone bad. But it is not at all a wise move to replace only these two. From experience of many technicians, the TV will make a revisit soon. Reason: New LEDs will draw less current whereas old will draw more. There will be a mismatch. Even in voltages. So, it is always replace the entire strips at a time. That is what experienced technicians do. Moreover, replacing the backlight requires removing the panel. While its ok opto 32" to 40", it is a risky thing to do with increased sizes. Many thanks for your comments and query!
Kageni
January 29, 2022 at 1:06 pm
Hello it's common for makes like LG to have all the lights go out at once. The common mistake is replacing the lights without replacing the streaming capacitors.soon the replacement blows out in less than tree months.
Parasuraman S
February 5, 2022 at 12:10 am
Many thanks for your expert opinion!
Joshua Oloo
January 22, 2022 at 1:19 pm
Thanks for the Article sir.what are the reasons for replacing all the caps on the board.Thanks
Parasuraman S
January 23, 2022 at 12:43 pm
When the LEDs become weak and start drawing more current, the electrolytic caps get the strain and it could happen otherwise also. So, as a precaution to prevent repeated failure, and to bring back the board to its almost perfect working condition, replacing electrolytic capacitors is resorted to. Many thanks for your comments!
Waleed Rishmawi
January 22, 2022 at 1:54 pm
that is a professional repair. in my home town I can not find the exact replacement unless I order on line and wait for it to come. the only thing I advice my customers when doing such repair is to not to crank up the backlight level all the way up but keep it meduim setting otherwise they will end up with the same problem. some people listen and do, others just listen and do not do and these are the people that their devices end up in my shop for repair. thanks for sharing and have a blessed day
Parasuraman S
January 23, 2022 at 12:45 pm
Many thanks dear friend! You are very correct! Seldom customers listen to wise advice, especially when they have adamant children around. Anyhow, such people serve as agents for giving us business, though unknowingly! (LOL)
Imoudu Onwumah
January 22, 2022 at 3:12 pm
Thanks for sharing this repair article,I have such led tv with combo board with problem of automatic increasing volume by itself,which I haven't been able to fix.From what I gain from ur article,I will try changing all e caps too and see what happens.Have a blessed day.
Parasuraman S
January 23, 2022 at 12:48 pm
Dear, look for jammed control buttons either on the panel or on remote. Remove battery from the remote and check whether the volume increases. If it does, the problem is on the TV side. The next possibility is a leaky cap or component on that circuit. Lastly, the software! Many thanks for your comments!
Albert van Bemmelen
January 22, 2022 at 4:06 pm
Those backlit problems are like a real pain in the back. They always require much time and patience before the bad led or ledstrip is dismantled and the problem is fixed. It is time that they start making new easily replaceable backlight plates that just shift out and in of the TV or Monitor case. So the device doesn't have to be opened for this type of repair anymore. Just like a dvd or blu ray disc that ejects out of the player or shifts right back in.
Parasuraman S
January 23, 2022 at 12:50 pm
You are very correct! Replacing a backlight is a real pain and time consuming! When the panels are very large, it is risky in doing too! Many thanks for your expert comments!
ivan rivera
January 23, 2022 at 12:28 am
Creo que eso acabaría con la obsolescencia programada o tener que reemplazar el aparato en corto tiempo,por una nueva tecnología manteniendo la continuidad de las fabricas ,eso ha hecho en mi país CHILE,la desaparición de los técnicos electrónicos dedicados a la reparación de artefactos de uso domésticos ,ya que se suman a e los televisores ,lavadoras ,refrigeradores ,hornos de microondas y otros
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I believe that this would put an end to planned obsolescence or having to replace the device in a short time, with a new technology maintaining the continuity of the factories, that has been done in my country CHILE, the disappearance of the electronic technicians dedicated to the repair of devices of household use, as they are added to televisions, washing machines, refrigerators, microwave ovens and other
Parasuraman S
January 25, 2022 at 9:23 am
Many thanks for your comments!
GIFT ELIJAH
January 23, 2022 at 7:05 am
A very good fix sir, am learning seriously from your wealth of experience
Parasuraman S
January 23, 2022 at 12:51 pm
Many thanks! Life is always a learning process and an opportunity from birth to death! In birth, we learn how to occupy the body and come out, and in death how to leave it!
Lynn Blakely
January 25, 2022 at 6:56 am
Dear Parasuraman: I enjoy reading your replies to inquiries. I liked the explanation of why to replace all the back lights, and also why to replace all the caps. Also you gave a solid procedure for finding the cause of the volume going up without anyone pressing a button, on the set or the remote. May you be blessed in this new year.
Parasuraman S
January 25, 2022 at 9:27 am
Many thanks, dear for your encouraging comments! I believe that every human being is born for each other, irrespective of cast, creed and country and we have certain allotted slot within which we are programmed to do so! It is this interweaving net like a dove's tail that keeps us progressing towards the universal goal!