How to Replace a LCD Backlight

by Ryan Merrick

156K3314

Intro: How to Replace a LCD Backlight

Here are some simple instructions on how to replace a burnt out LCD backlight with a new working one to bring your LCD back to life.  Inevitably, every LCD eventually goes dark, but the process to bring it back to working order is not very hard.  As long as you are careful, it can be done successfully and without too much drama. Generally this is a very cheap repair, usually only around $10-20.  

This instructable will be performed on a laptop LCD from an old Zenith Data Systems computer.  I tried to make this instructable pretty basic and not extremely detailed because every LCD screen is different. Your LCD will be different from mine (how its held together, the number of CCFL's, etc) but the concepts will remain the same.  Feel free to send me any questions you might have, and I'll try to help you out.

Materials:

Replacement CCFL (Cold Cathode Fluorescent Tube) 

Tools:

Small Phillips Screwdrivers
Torx Screwdrivers
Electrical Tape / Soldering Iron



STEP 1: Disassembling the LCD Housing

To get the the LCD screen and the backlight inside, you must first disassemble the LCD housing; this is different depending on whether it is an external monitor, or built into a laptop.  But first before disassembling the housing, DISCONNECT THE POWER!

EXTERNAL LCD MONITOR: Usually to get inside of an external monitor, you will have to simply take out all the screws on the back of the display and pull it apart.  Pretty simple.

LAPTOP LCD (Shown): This can be a little more frustrating at times, but not impossible.  First open up the laptop and locate all of the screws (sometimes these can be hiding under rubber feet).  After removing the screws, many times you will also need to use a flat head screwdriver to pry the housing open little by little.  Be gentle,, but don't be afraid to use a little force.

After getting the back of housing off the computer, disconnect the LCD from the inverter.  

Now completely detach the LCD from the housing by removing the remaining screws.

STEP 2: Taking Apart the LCD Itself

Now comes the most interesting part (and the part where you must be the most organized and careful!), disassembling the LCD itself.  

In this step make sure that every element of the LCD you remove is kept in perfect order so you can easily reassemble it after replacing the lamp(s).  The LCD I am disassembling really didn't require me to remove too much to get to the CCFL's, but many times you will need to remove several layers of transparent sheets that are used to spread the light uniformly throughout the screen.

Just like before, locate and remove the screws holding the LCD assembly together.  Take the assembly apart including any transparent sheets in the way of the cold cathode tubes.

REMEMBER! Stay organized for your own sake!


STEP 3: Remove the Backlight

 In this step you must be very gentle.  The lights contain mercury and are very fragile.  This step is not that difficult, just be patient.  Do not use any force when removing the CCFL or it will break (I speak from experience).  I would suggest that you loosen the wires from the LCD first and then gently remove the CCFL.


STEP 4: Insert Your New Backlight

 Take your new CCFL and insert the lamp exactly where the old tube was located.  Again, be gentle and this step will be easy.

After inserting the new CCFL and routing the cables correctly, reassemble the LCD the same way you took it apart.

STEP 5: Test Out the Display

After putting your LCD back together, reattach the inverter and any other cables that may have been connected to the display.  Next, before putting the housing back together completely, test out your display to make sure everything is in correct working order.

NOTE: Be VERY careful with the exposed connections and cables, ESPECIALLY the Inverter. Touching the wrong part could not only hurt you, but damage your display.  Yet again, I speak from experience.

STEP 6: All Done!

Make sure all your connections are tight, and theres no extra screws.  Finish reassembling the LCD housing and you're all set!  

Again, feel free to send me any questions, comments, or suggestions for this Instructable!

Thanks for reading!
Ryan Merrick

12 Comments

KalliasX 4 years ago

Ok so here is the deal. My screen was working well. Then a small spider showed up on it every day (on the glass, not under)... a tiny jumping spider, and I got attached to the little guy cause it was chasing my mouse pointer! I thought that was sweet, even if it would sometimes leap and attack it :D... which makes me think maybe the death of my monitor is related. It's a Philips BDM4065uc, 4k. I LOVED that monitor. For 10 days the spider was around... every day. I once removed it and put it down at the other side of the room, next day it was back on my screen.

One day the top 1/3 of my backlight was down 50% in luminosity... but the spider was gone. Never saw it again. 5 days later, the backlight zones flickered, and 3 minutes later it was dead. My theory is that the spider went in, and something unfortunate happened. So mind you the spider was cute but not 680$ cute :). Oh well.

So I connected my monitor and a chrome TV and shone a flash light on it, I can see the Reconnect Me font from my chrome TV plugged in. So the screen works, just don't have a backlight.

In your opinion, what should I do to try and fix this? Can I buy a backlight? could it be a board? a bulb?... I'm no electrician but I build my own computers, repair them, repaired or upgraded cpu/gpu in laptops, so I'm thinking I should be able to fix this (skill wise).

And before I finish opening this thing up (mostly to look for a spider corpse at this point to confirm my theory), is there dangerous capacitors in such beasts?

Thanks in advance
Best regards

Chris

Legus 7 years ago

I have an old samsung SGH-A77 ( https://www.att.com/support_static_files/manuals/Samsung_A777.pdf ), but it has received some water damage, and the backlight no longer works. Everything else appears to be in order, including the LCD itself, but the LCD and the backlight are pretty much one thing. Any idea on how to go about fixing this so that I don't have to buy a new phone?

diy1437 8 years ago

I replaced the CCFL bulb on my HP DV6-1030US 16" screen laptop. I also replaced the inverter. The screen now turns on and lights up, but the brightness is not as bright as it should be. It is about 50% or less of it is supposed to be. I reset the PC by holding the power button for aprx 2 mins without power on or battery What could it be wrong? Please help

mizapilah 12 years ago

What if u replace the CCFL with a Led strip? Could the led strip be connected directly to the 12vdc or 24vdc, skipping the inverter? Pls helpme.

Ryan Merrick 12 years ago

Hey,

Yeah, you could definitely hook up an LED strip to do the backlighting....many TVs are doing that nowadays.

Can't give you a definite answer on connecting it to power however. I would imagine it would depend on what exactly you are using as far as the LEDs are concerned.... I'm sure if you look hard enough for a product online you could find something that would work

Mouseinhat 13 years ago

Nice instructable
Can you tell me where to get ccfl tubes from, as I have a use for them in a project I'm making.
Thanks

kbhasi 13 years ago

lol at the custom boot screen for win 3.1...

Scott_Tx 14 years ago

Is there any way to tell if its the inverter or the bulbs that are bad without having spares to swap?

Ryan Merrick 14 years ago

 Hey,

It can be a little more complicated with out spares, but usually it's more common for the inverter board fail first.  It's annoying because both can have similar symptoms.  

If the LCD is on and running (still dark) but you can still see a faint image, then its either the inverter or bulb.  If you can't see any faint image at all, or if weird things are going on in the screen (lines, craziness) then I would check to make sure all your connections are tight (especially on a laptop).

However the symptoms listed below usually point to the bulb being the issue:

1. The screen starts off working fine, but then it starts flickering and shuts off, but at the same time you see a faint image (shine a flashlight)

2. The screen lights up for a few seconds then shuts off (external output still works perfectly)

3. The screen works but has a red or pink hue to it (external output still works perfectly)

I hope some of that helps!  Don't hesitate to ask more questions!

Scott_Tx 14 years ago

I've got an old 15" in the junk pile someone gave me that only works if the inverter board is unplugged. I 'm pretty sure thats a sign that the inverter is bad but wondered if there was a way to test them.

Ryan Merrick 14 years ago

 Ok yeah I agree, it does sound like an inverter problem.  

One option I would do if I was in your situation would be to just stop playing with the current bulb and inverter, and simply buy a new cold cathode bulb attached to its own independent inverter.  Install this setup in your monitor and basically you would just flip the switch on the new inverter, and turn on your monitor and you would be all set.

I just saw one the other day for $10....i'll send you the link when i find it!