LED Backlight for an LCD Monitor or Television

by drew.adc

247K9771

Intro: LED Backlight for an LCD Monitor or Television

Non-working LCD screens can often be found cheap or free. I started doing this originally because I needed multiple screens for schoolwork but didn't want to fork out the money for a brand new one. The key to getting a suitable one for this Instructable is to get one where the screen itself is not broken. This Instructable will describe how I replaced the CCFL (Cold Cathode Fluorescent Lamp) backlights with LED strips. The advantage to using these instead of single LEDs is that the LED strips can be purchased cheaply on Ebay and the monitor can be completely reassembled because the LED strips take up less space than the original CCFL backlights. This means that externally the modified screen will look just like a stock screen.

From my experience, these non-working screens usually have problems with either the power supplies or the inverters for the backlights. Often times, these problems are easily fixed by replacing bad capacitors, but occasionally the problems are different. I managed to accumulate several screens with problems with the inverters I was unable to diagnose with a reasonable amount of effort, so I decided to replace the backlights with LEDs, thereby cutting out the faulty inverter circuit.

DISCLAIMER: This instructable involves opening and modifying electrical devices and handling bulbs that contain mercury. It is meant to be a recollection of the process I used to modify my personal monitor, not a step by step guide for all monitors. Do not attempt this Instructable unless you are qualified to do so. Be sure you are comfortable and qualified before attempting any Instructable and be sure to always disconnect power before working. I cannot be held responsible for anything that comes about from attempting to replicate this Instructable. Attempt it solely at your own risk.

STEP 1: Tools and Parts

To complete this project, I used the following tools and parts.

Tools:
Soldering Iron
Screwdrivers
Wire Strippers
Solder

Parts:
Self Adhesive Surface Mount LED Strip
Wire
Electrical Tape

STEP 2: Disassemble Your Screen

I will not try to explain how I opened my screens because each one varies so much. The biggest thing was to make sure I could put the screen back together once I was done. Basically though, I needed to open the outer plastic case which is usually held together by screws and snaps first. Next, I usually needed to remove a metal cover on the back of the newly exposed inside of the screen. This should expose all of the circuit boards, so I could now unplug the CCFLs from the inverter board. I needed to continue this disassembling until I could remove the metal holders containing the CCFLs. In all of my screens, there is one on the top of the screen and one on the bottom.

CAUTION: By disassembling my screen this far, I exposed the very fragile parts. I used extreme caution to avoid breaking anything.

STEP 3: Dispose of the CCFLs

Next, I needed to carefully remove the CCFLs from the metal holders. I needed to be extremely careful because each of the lamps contained mercury. This also meant I needed to dispose of them properly and responsibly.

STEP 4: Add LEDs

Now that the CCFLs have been removed, I could cut an LED strip to as long as possible where it still fits in the metal holder from the CCFLs. I then needed to solder wires to the positive and negative terminals of the LED strip. Then, I peeled off the backing and stuck the LED strip in the metal holder with the LEDs pointing towards the screen. The wires should exit the same side of the screen as the original wires from the CCFLs. See the picture for more details.

STEP 5: Reassemble Your Screen

Now, I could reassemble my screen with the metal CCFL holders in their original place, but now containing LED strips instead. I had to be sure to take my time and carefully assemble the screen correctly. Also, be sure to route the wires from the LED strips in the same way as the wires from the original CCFLs. Do not go so far as to cover up the circuit boards yet.

STEP 6: Remove Inverter Board and Connect LEDs

Now that I have replaced the CCFLs, I can remove the inverter board as long as it is completely separate from everything else. My LED strip runs off of 12VDC, so I had to find a source and neutral point to solder the wires to. From my experience, this is a very common voltage in LCDs, but make sure to find a 12V source that is off when the screen is off and on when the screen is on or else the LED strips will always be turned on while the screen is plugged in. Also, make sure it is capable of supplying the necessary current for the LEDs needs. I wanted to use a fuse on the 12V line to be safe. Once I attached my wires, I needed to secure them so they don't move around or get pinched during the final reassembly. I could now continue to reassemble the screen until it is completely put back together.

STEP 7: Test and Enjoy

If I connected everything correctly, I should now be able plug the screen back in. When I turn it on, I noticed that it is slightly dimmer than a regular screen depending on the LEDs used. Also, depending on how far apart the LEDs are on your strip, I noticed some slightly bright spots near the edges where the strips are placed.

I have not noticed any significant bright spots, but have noticed the screens are a bit dimmer than an unmodified one. It is especially apparent when the screen size gets above 19 inches. Also, the dimming function no longer does anything. While it may not look quite as good as an unmodified screen, a screen with LED backlights is more than acceptable when I realized the only part I had to pay for was probably the LEDs. If I used better LEDs than I did, I could probably make a screen that looks better than the original.

I tried to get a picture of the bright spots. These pictures were taken at an angle towards the LEDs with a solid white screen displaying. The screen looks much better from straight on and with something other than a solid white screen.

69 Comments

StewardC 6 years ago

how much is it cost , BAcklight strips for my samsung smarttv UA-40-f550??

Where i can buy LED bulbs

rAj243j 7 years ago

Hi. How much does the Backlight strips cost for Sony LED TV 40R452A?

Sony service person says that the panel costs around 270 USD

TheKitMurkit. 7 years ago

Please show us how it handles displaying colors!

Chu Guk 7 years ago

Awesome project. The only problem I seem to have with my Sony Bravia is that it shuts off if the inverters are unplugged. Is there a way to get around that, or is it some other problem with one of the other boards?

ricardprospe-0 7 years ago

insignia #model ns-p16ato8

KostantinC 7 years ago

I replaced CCFL backlights with LED on my SONY - KDL 46CX520 ,i did everything right,tv is working but there is one problem that i don't know how to solve i need help.Problem is the white stripes from the LED that i see them in the picture like shadows,like white lines,it is totally irritating. HELP !

NelsonM33 8 years ago

i have 32 inch samsung led. recently screen display wen dark and only very blur image is visible. any solution please share.

LyndonL2 8 years ago

,.hi,. am an aspiring technician,. i have same problem with my LG 32ln5100 led tv.

and i found out that one of the LED backlight was busted.. so i checked the supply board and with the voltmeter, and i got less than 1 volt,.

AgaK 8 years ago

Great but to little details. If I have 12 CCFLs do I need to replace them with 12 strips? What about inverter? What to do with inverter after this modification?

mseromenho 11 years ago

Hi, first of all thanks very much for your effort's helping other people :)

I am a experienced computer maintenance tech, but here in Portugal it's a bit difficult to find parts like this.

What I'm searching for it's a led strip for a LED Screen from an ACER ASPIRE 5111. Any idea where to buy this? I have been searching but I'm not sure if my search key's are not very accurate or other reason.

Thanks!

Xxbaxinxbsxx 9 years ago

Not sure if you already looked at these: http://www.lcdparts.net/XBDetail.aspx?ProductID=3745

drew.adc 11 years ago

Thanks for your comments. I unfortunately do not know where to buy this specific strip. For my project I used a generic LED strip from eBay however I doubt it is small enough to fit into a laptop or that it would perform the way you want. Best of luck in your search.

mknorr 9 years ago

I think the real hazard would be the broken glass rather than the tiny amount of mercury. I know that mercury compounds can be hazardous but having spilt about a teaspoon worth of mercury on my bedroom carpet as a kid, I never had any affect from it.

agulesin 9 years ago

Apart from your deep yellow skin tone! ;-)

smoak 10 years ago

I was looking to do something like this with a TV my friend got from his uncles camp. I've checked it out and taken it apart, and the screen still works fine just the lights won't work. They slightly come on for about 5 seconds or less then immediately go out and won't come back on unless you shut it off and start over. Kind of like when your fluorescent bulbs are starting up but failing to light. When I took it apart there were about 15-20 very long and thing bulbs. So my question, would this method work on this? It's a 36? inch Polaroid TV.

cobast 11 years ago

Spent hours googling for an article like this. Great work!
I want to make a daylight visible display for our skateboarding club to use outdoors. These have a brightness of around 1000+ nits whereas normal monitors are about 400 nits. Do you reckon if I carefully inserted sufficient LED strips it could work? Maybe triple strips? I already have an LED power supply and dimmer to take care of power supply if it is an issue with the extra LEDs. I haven't opened a monitor up yet but I have a few available. Any thoughts / suggestions?
Please don't suggest buying a proper daylight monitor as they cost BIG money.

-=Dr.Who=- 13 years ago

I've read the process twice now and there's 1 thing you left out...
Where did you get the self-adhesive, cut-to-fit LEDs!?!?! And how much you got & what you paid for it?
I've never seen stuff for sale anywhere. and have many other uses for that kind of LED stock in my lab. Please tell us where you got it from!!!

drheqx 11 years ago

You can get the LED strips from parts express
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=073-069

drew.adc 13 years ago

From one of my comments below:

"I bought mine from eBay. Specifically, I bought these: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200388725627&ssPageName=STRK:MEWNX:IT

It is actually only 150 warm white surface mount LEDs on an 8 foot strip, not 300 like the ad says later. The 8 foot strip was enough to do two 17 inch monitors and one 20 inch television and have between 1 and 2 feet leftover. I know that you can get twice the length for not much more money. If I had to do it again, I would probably get the longer strip and get them in cool white to try to get a better color and brightness. Just make sure that they are narrow enough to fit into your CCFL holder."