Four Different Cases Of Backlight Issues
As mentioned by me before in a few articles, these are cases which I attended to in my friends’ shop. I am sharing this with brief description and pictures for those who are interested in knowing the issues, resolutions and also to have view of the inside of the sets.
Case 1:- Make: Haier – Model: LE32M600C – Complaint: Low glow at bottom
After opening the set and checking the backlight with an LED tester and also the output of the LED driver on the board, it was confirmed that the issue was with the backlight. So, removed the panel and replaced the backlight.
After replacing the backlights, the issue was resolved, as you can see from the following picture:
Case 2:- Make: Panasonic – Model: TH-24C400DX – Complaint: No backlight
In this case, it was detected that the LED Driver was defective, as the backlight was ok when checked with the backlight tester. As it was a combo board, the best solution was to provide an LED inverter board. The 12V supply and ground was tapped from the combo board.
The power on was taken from pin 10 of the inverter IC. This universal LED Inverter board had multiple connections in the output and the appropriate output suitable was selected. Just see the connections:
After checking all work done, when the set was switched on, it worked perfectly well:
Case 3: Make: Videocon – Model : LWDTWKC40FH-ZMA – Complaint: No backlight
After doing the preliminary checks of backlight with the LED checker, the focus was turned on to the inverter board. Indeed a completely dry soldered transformer was found.
After cleaning the area very well, fresh solder was applied and when the TV was tested, it worked very well:
Case 4:- Make: Videocon – Model : V3218LEDTV – Complaint : Blinking backlight
This Videocon TV belonged to my colleague in the Hospital, and was the one in which the panel was changed. Subsequently, it developed a problem with the backlight and the Mosfet was changed by my friend, as the panel change work was done in his shop.
Again it came to his shop, as per my directions and when I opened the set; I noticed that the LED driver itself was having a problem. It was switching on and off. Instead of wasting time on troubleshooting the board (as per his shop policy), an LED driver board was fixed on top of the heat zinc using the screw of the Mosfet as fastener.
The 12V supply, ground and power on was taken from the board.
The TV was found working very well after doing this bypass surgery!
Thus missions accomplished and satisfactions got collected!
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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AJAYAKUMAR SOMADETHAN
January 20, 2023 at 11:37 am
Thanks for sharing your experience
Parasuraman S
January 20, 2023 at 1:56 pm
Many thanks!
Albert van Bemmelen
January 20, 2023 at 1:41 pm
The last mentioned repair with the led driver bypass was the most interesting fix. Sadly you didn't mention the exact type of led driver board that was used. Which would have made it even more interesting in case one would need such a led driver board too.
Parasuraman S
January 20, 2023 at 10:38 pm
That was a board given to me by my friend. Anyhow, these boards are commonly available in this part of the country. Many thanks for your comments!
Waleed Rishmawi
January 20, 2023 at 8:46 pm
thanks for sharing your experience. have a blessed day
Parasuraman S
January 20, 2023 at 10:38 pm
Many thanks, dear friend!
ANIL KUMAR V K
January 20, 2023 at 11:07 pm
Thanks for sharing
Parasuraman S
January 21, 2023 at 11:12 am
Many thanks!
Babu M S
January 20, 2023 at 11:52 pm
Many thanks for at a time your shared four cases.May please give details of led driver.
Parasuraman S
January 21, 2023 at 11:13 am
LED driver boards are easily available in the market. There are universal boards too with multiple pin connectors! Kindly get in touch with your local shop! Many thanks!
James A. Webb
January 21, 2023 at 1:02 am
Thanks. I had not heard of a universal LED Inverter board. Will look this up.
Parasuraman S
January 21, 2023 at 11:14 am
Yes, you should! Many thanks for your comments!
Tito Kanshulu
January 21, 2023 at 1:32 pm
Thanks for the experience shared Mr Parasuraman. We have picked one or two things from the articles.
Parasuraman S
January 21, 2023 at 7:47 pm
Glad to know! Many thanks for your comments and encouragement!
Yogesh Panchal
January 27, 2023 at 2:08 pm
Good job!sir,
This is called hunger of passion with dedication.
Parasuraman S
January 28, 2023 at 4:48 pm
Many thanks!
Mike retz
January 30, 2023 at 8:24 am
Hi reminds me of 6.3 volt booster xfmr for old crt sets. They called it. Bomb and would boost the 6.3 bolts on crt filament to about 7 volts when crt was bad.would hang off crt socket! Some were so big it would pull plastic cap off crt. Those were the good old days when cust didn't want to pay for new crt..21ap22 25xp22 etc. Thanks for great articles. Your the best. Mike USA..
Parasuraman S
January 31, 2023 at 7:54 am
Many thanks for your comments, encouragement and sharing of your experience!