LCD to LED TV modification

For many years, I have used countless info and tips that I found on the internet. Finally I decided to give something back by describing some of the repairs that I have done.

I will start with the most current one: LCD TV repair by turning it to a LED TV

I have a 8 years old 32 inch Samsung LCD TV at home. As you know, 8 electronic device years is 80 years in human years. Three weeks ago my old TV had a serious illness. Once I turned the TV on, the image came up only for a split second followed by a black screen. The sound kept going but it is not fun to use the TV as radio.

My first reaction was to see if there is visually something wrong in the TV. I replaced a capacitor which looked faulty but it did not work. From the internet, I saw that it was a problem with the back-light.

For those who don't know how LCD TV's work, here is a brief explanation:

As it's name implies LCD (liquid crystal display) TV's have a liquid crystal display in front, which produces the actual colored image probably by using liquid crystals (This part is out of my scope so this is all I know) :).. This display is fairly transparent and without a light source it is impossible to see it. This light source is called  back-light. LCD TV's use florescent tubes at the back to produce white light for us to see the image. LED TV's have the same display layer in front but uses hundreds of LEDs as back-light.

Once I found out that the problem is not repairable, I took it to the nearest Samsung service. The answer was simple: "we have to replace the flat panel for 700$". Since a similar brand new TV costs around 450$, I decided to play around with my broken TV.

The next day I disassembled the TV up to its florescent tubes.

This is what it looked like..

This is the actual LCD display

Housing for the florescents

and the florescents themselves..

At that moment I realized that it could be repaired by replacing the florescent light by LED strips and turning the LCD to LED TV. I ordered 10 meters of 3 chip white LED strips. The reason for a 3 chip LED instead of a single chip one is to ensure that I would have sufficient lighting.

I placed 14 lines of 70 cm LED's in the exact place of my 8 broken florescent tubes. You might ask "Why not 16?". The reason is simple: miscalculation. I wanted to put two strips for each tube but 10 meters was not enough :)

The next problem was to build a power supply. Old florescent lights were using 24 volts but my LED's
needed 12 volts. I chose the simplest way and used a 7812 voltage regulator for each strip and placed them in the florescent light driver case. This is a simple part which decreases the voltage to 12 volts. However it gets hand burning hot when you use 24 volts input for 1 ampere output.


Long story short my power supply got so hot, I had to use 3 computer fans to cool it down.



The final result was impressive. There are very narrow dark areas on top and the bottom of the screen which is very hard to notice, and you can hardly spot the strips on white screen.

After a successful operation, I added more years to the life of my old TV for only 50$ (plus around 5 hours of labor of course). I know that it would be much more simple to buy a new one instead of spending all that time, but its not just money. The joy of accomplishing such a repair is also a big factor. I'm just happy that it worked :)

Thanks for your attention.
Please don't hesitate to comment or ask questions.

My next blog will be probably about the modification of the shifting system for my old Citroen C3.
Until then take care..