Introduction: 80cm Broken LED TV Turned Into 50W Remote Controlled Light Box

Picture of 80cm Broken LED TV Turned Into 50W Remote Controlled Light Box

Today we will transform a broken 80cm LCD TV into a remote controlled light box for light therapy.

I brought the TV for cheap money as the LCD was broken. The TV used LED technology for the back light and everything worked fine. It's form a Chines brand "HARROW", nothing special.


Step 1: Open the TV

Picture of Open the TV

The first step: open the thing: very simple, unscrew the screws ...
That is how it looks like inside.

Step 2: Remove the LCD Panel

Picture of Remove the LCD Panel

Now we need to remove the LCD panel and only keep the back light system.

To do this we need to disconnect the LCD panel from the main board and unscrew the screw that hold the LCD in place (the metal bars on the sides). Now we can see the back light system, which is basically just a white surface.

Step 3: Hack the Brigthness Control System

Picture of Hack the Brigthness Control System

When you use you're TV as usual you can control the brightness with the remote control. As we don't have access to the configuration screen any more (as we don't see it ...) if we want to use the full power of the back light we need to hack the control system.

To do that I first checked the datasheet of the panel. My panel is a LG LC320DXN. You can find the data sheet easily on duckduckgo or google.

Going to the back light module specification shows us that the back light power is controlled by a PWM pin on the inverter board. There is also a pin to enable/disable the entire panel.

If we always want the maximum power out of the LEDs we simply need to put always a high logic level on the PWM pin. So I simply cut the PWM cable and soldered it on the enable/disable pin. If the panel is on the enable/disable pin will have a logic level high (5.0V) and so the PWM will be at maximum.

On the board, the pink wire is the PWM wire, just cut it and solder it on the enable/disable pin, here the gray one.

Step 4: Result!

Picture of Result!

Now what do we have? A remote controlled light source!! Yes, it you power up everything again, the TV will light up as usual if you use the remote control. Of course the TV does not know the LCD is not connected any more!

As we hacked the brightness system the light power will be at maximum all the time.

50W of LED is quite powerful!

Step 5: Bonus 1: Take a Deeper Look Inside

Picture of Bonus 1: Take a Deeper Look Inside

Just to see how it is made inside I took a deeper look inside. If you remove the black platic holding the back light system together you will be able to see 4 optical layers. (on my photo there are only 3, I removed the upper one because it's kind of a polarizing filler only useful for the LCD panel). The last layer is a 3 mm white platic pane and
the 2 upper ones are translucent paper to make the light as uniform as possible.

If you remove them you will finally see the LEDs.

Step 6: Bonus 2: Remove the Remote Control to Use a Wall Interrupter

Picture of Bonus 2: Remove the Remote Control to Use a Wall Interrupter

Okey, this is pretty cool but useless when you want to use the wall interrupter as with usual lights. So lets take a look at the back of the screen: There are 2 boards: the green one for the logic and the beige one is the power supply. We need to get rid of the green one and to do that we need find the different enable pins on the power connector between the two board.

This is quite complicated and I would not recommend you to do this if you’re not sure about what you’re doing. Keep in mind that there are life dangerous voltages in game. I checked the different cables with a multi-meter and found out 4 cables:

-one delivering a 3.0V – 4.0V unstable voltage when the power supply is on standby and 5.0V if the power supply is enabled

-one that if connected to 3.3V enables the power supply

-one that if connected to 3.3V enables the back light

If we connect them together we have:

-the power supply enabled

-the back light enabled

and finally it works as a usual light: put 220V on the power supply and it will light up!

Comments

SaraM195 (author)2017-08-01

Anyway you could help me? I cant find a datasheet nor do i honestly know what im doing i can give you my email address

cherry.miller25 (author)2016-12-22

Hi ...

Its a really impressive work...

Can you me help in understanding the power supply specifications for the led backlight from my broken tv "Vizio E320-A1"

I searched in duckduckgo (or google) but its not very clear to me.

I want to use these led lights to make a softbox.

I would really appreciate your help ....

hubi (author)2015-12-20

I sould have read this before. I made a lightpanel out of another LED TV. Mine has 5 of the same LED strips that you have in yours. Each consisting of 9 LEDs in series, the stripes are also in series, i measured it was powered by 146V 330mA. When I turned it on via TV remote it went off (standby) after a short time cause there was no signal. So I built my own supply. I power the strips in parallel with a old 19V laptop supply and an boost converter set to 30V the strips are now in parallel, each strip has a 2.7 Ohm resistor in series, the current per string is only 150mA that is bright enough to me, with 330mA per string it does not get much brighter. I use this lightpanel as therapeutic light against the winter blues. My Screen is from a tv that fell down so the LCD was broken.

fefesplace (author)hubi2015-12-22

You could also take a look at constant current (C.C.) power supplies. Some years ago they where expensive but nowadays the price is acceptable. I guess you could easily find a C.C. supply of 150mA for a voltage range of 10-35V. And if you have more strips in parallel 1A C.C. also exists.

Take a look here:

https://www.instructables.com/id/Turn-a-broken-22-d...

steampunkpotato (author)2015-04-11

if you wanted to, you could make a frame around it, and put glass over the led's and make a light table :)

fefesplace made it! (author)steampunkpotato2015-12-10

I finally got the time to do that!

Yonatan24 (author)2015-12-08

That's so EPIC!

I've been wanting to do this for a long time but I can't find flat-screen TV's anywhere :(

rec2hd (author)2015-03-04

it work's fine with LCD panels too. but one has to be very carefull with the AC cord voltage and the HVAC voltage to the neon tubes.

tomatoskins (author)2015-02-19

This is a great idea! Now I know what to do with those old tv's I have lying around.

fefesplace (author)tomatoskins2015-02-19

Thanks! Just be careful is you have non LED tv's, those will have neon back light and may use high voltages (1000V).

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