LCD screen
A laptop screen also known as LCD screen displays an image generated by the laptop video card. The LCD screen receives data signal from the video card through the LCD cable.
Laptop screens come in many different sizes and resolutions. In order to find the LCD screen size (in inches), you’ll have to measure the screen between the two diagonal corners.
Older laptops had mostly full screen LCD displays. Newer laptops have mostly widescreen LCD displays.
A backlight lamp (also known as CCFL bulb) is the main source of light in any LCD screen. The backlight lamp powers up by the inverter board.
The LCD screen mounts inside the laptop display panel between the screen bezel and display cover. The LCD screen is attached to the screen brackets (display brackets) which are permanently attached to the display hinges.
TYPICAL LCD SCREEN RELATED FAILURES
On the following images you’ll see some typical LCD screen related failures.
1. You can see image only on a part of the LCD screen. For example, only the top side of the screen works properly.
2. There is one or more thin multi color lines running down the screen.
3. There is a wide band running down the LCD screen. The
BUYING A NEW REPLACEMENT SCREEN
The LCD screen is one of the most expensive parts in a laptop computer. If your screen is damaged and you decide to replace it yourself, you’ll have to make sure to purchase a new screen compatible with your laptop. Hear are a few things to consider before buying a new screen:
1. Screen size.
2. Some laptops come with full size LCDs. Some laptops come with widescreen LCDs.
3. LCD screen could be matte or glossy.
4. Same size LCD screens may have different resolutions.
The best way to find a new replacement screen would be using the manufacturer’s part number or LCD screen model. Both could be found on the back side of the screen.
August 22nd, 2010 at 7:28 pm
Brad,
I guess in your laptop BIOS you cannot choose the primary screen. Otherwise you would see that. I asked just in case because all laptop BIOSes are different.
Double check all connections between the video cable and LCD/monitor. If all connections are fine but the problem still there, it’s possible there is something wrong with the motherboard.
August 22nd, 2010 at 9:14 am
Have a Satellite A135 where the screen only lights up occasionally, and is usually all red in color. Connected to an external monitor is always OK for color and the picture is fine. What is usually the culprit in this case.
August 20th, 2010 at 5:54 pm
I checked and the only settings I see in the bios is the brightness. Do you have a step by step?
August 20th, 2010 at 4:50 pm
Brad,
Take a look at the BIOS settings. Maybe the external monitor is set as a primary screen? Can you change settings and make laptop LCD the primary screen?
August 20th, 2010 at 4:39 pm
Hey I have a question. I just replaced my lcd screen on my dell inspiron 1520. I also replaced the power inverter. Now during start up my screen becomes backlit, then goes out and will not come back on. I can connect an external monitor, use my function key and there is my computer on my external screen. I use my function key again to switch to both modes, and there is my new lcd screen. I use my function key again to set to only my laptop and it works fine. Once I reboot, everything goes back to not working again. I have checked the bios, but nothing seems to work. Any hints?
August 11th, 2010 at 10:28 am
kenny,
If the laptop works fine with external monitor, this is not video card related failure.
Most likely it’s either bad video cable or failed LCD screen.
Here’s what you can try:
1. Try reconnecting the video cable on both ends, on the motherboard and LCD screen. Make sure it’s not just connection related problem.
2. Try moving the video cable while the laptop is turned on. If moving the cable affects video on the screen, most likely this is bad cable. If moving the cable doesn’t affect video on the screen at all, most likely this is bad screen.
August 11th, 2010 at 4:24 am
Hi
laptop is presenting multicolor lines in the screen, blocking mouse and image. Sometime did work when we moved the screen back and forward, now just multicolor lines on the screen, is working perfect with external monitor. amilo pro v3505.thank you for you help
July 29th, 2010 at 9:15 pm
Dennis,
I think you are correct. Sounds like a problem with the motherboard. Probably not worth repair.
July 23rd, 2010 at 10:27 am
Hi Repair Man,
Thanks for your suggestion under post 89. The lid close button appears to be working OK. Also the Fn + F5 function is now closing/opening the external monitor, but nothing appears on the laptop screen other than a very faint image.
The low voltages through the inverter connection looks to be the problem, which I believe indicates that the motherboard is the cause. I do not think it is worth repairing, unless you have any further ideas. Appreciate your help.
Dennis
July 22nd, 2010 at 11:46 pm
Rajesh,
Most likely the LCD screen was damaged.
Depends on the type of warranty you have.
July 22nd, 2010 at 11:28 pm
Brian,
Sounds like the video cable problem to me.
Did you buy the replacement video cable from a reliable source? Maybe the new cable is bad?
Make sure the cable is plugged correctly into the motherboard. Double check the connection.
July 22nd, 2010 at 10:42 pm
Dennis,
You are correct. Most likely this is not screen related problem.
I’m not familiar with this model but I think you should take a closer look at the lid close switch on the laptop A. Is is a physical button?
Maybe the lid close switch is dirty and got stuck inside the case? Try tapping on the lid close switch while the laptop A is turned on.
I had a very similar problem just recently and it was an Acer laptop.
1. I tried a good working screen on the laptop and the backlight didn’t work (even though I had a very faint image).
2. I purchase a new inverter and it didn’t help either.
Only after I pressed on the lid close switch many times with a small screwdriver, the backlight turned on and started working properly. It was a tiny switch close to the right hinge.
July 21st, 2010 at 7:46 am
Hi my new laptop had accidentaly fell down and now the screen is displayed in two different resolutions. Left side shows the actual resolution and the right side shows a slightly dull resolution. Is there any way to rectify the issue? Will this cover under warranty? I heard the lcd monitor is one of the costly part in the laptop. Kindly revert. Thanks in advance
July 17th, 2010 at 8:15 pm
Hi there,
I have a problem with my HP DV9700t Laptop.
My new laptop display won’t work. Original problem occured with intermittent flickering when lid was moved. This I put down to bad display cable and ignored (bad idea in hindsight). Display finally flickered , had a white cloud and then black. Laptop boots up fine and backlight turns on when it’s supposed to but screen remains blank. Works perfectly through external monitor. I then replaced the display cable with no change. Replaced display with brand new identical and no change. I tried hooking it up with an old 14″ display (mine is 17″) and sure enough i could make out my background on display (image was dark but no backlight on as cables were different).
I’m stumped now to what my problem could be and if anyone has an idea I greatly appreciate it.
Regards,
Brian.
July 13th, 2010 at 9:31 am
Hi, I have two Uniwill/Tiny 755SI4 laptops, which I will call A & B.
The A machine screen will not power up the screen although you can see the image faintly in the background. The A laptop provides a perfect picture through a remote monitor.
If I exchange the screen on laptop A, and connect it to laptop B, the screen works perfectly. However, the screen originally working on laptop B also only shows a faint image when connected to laptop A. This suggests that both screens are OK and the problem is possibly with the motherboard.
The screens both have a separate lead for video and inverter. The inverter has 6 wires connecting to the motherboard’s 12 pin connector. Pins 1 to 5 and pin 12 as ground. Voltages for laptop A with the inverter connected are as follows :
pin 1 – 2.8v, pin 2 – 2.8v, pin 3 – 1.8v, pin 4 – 2.71v pin 5 – 0.0v, but the screen is not showing a proper image. If I disconnect the inverter cable (leaving the video cable connected) the voltages are : pin 1 – 18.78v, pin 2 – 18.78v, pin 3 – 1.87v, pin 4 – 3.24v, pin 5 – 0.0v. On the fully functional laptop B the voltages are : pin 1 = 19.48v, pin 2 – 19.48v, pin 3 – 0.51v, pin 4 – 2.30v pin 5 – 0.0v.
As I have proved that both screens are fully working on laptop B, and the voltages from laptop A motherboard without the inverter connected are similar to the those of the fully functional laptop B, I am confused. I have noticed that the FN + F5 key will not close down the external monitor connected to laptop A.
Any suggestions to resolve this problem are welcome. Many thanks.
Dennis
July 12th, 2010 at 9:57 am
Lara,
I’m glad to help.
I can with laptops but not desktop LCD screens.
If the LCD monitors shows garbled image, it’s either bad cable or the monitor is bad and has to be replaced.
July 12th, 2010 at 3:00 am
Hi,
You can never ever imagine how much my joy goes here.
LCD cable was disconnected just as you suggested.
You saved my mostly new laptop.
Thank you so much !!!
Before coming to this site, I’d red hundred of pages about LCD issue. You just earn my time & money.
You’re awsome.
(Maybe, in some days or from time to time, I’d like to ask another LCD monitor problem. It gives similar image like your above pictures. I’m not sure if you can accept my questions, since it’s not related to laptop, but only LCD monitor.)
July 8th, 2010 at 10:46 pm
Lara,
First of all, try switching video from external to internal mode. Usually you can do it using the Fn key and one of the F* key. For example, on my Toshiba laptop I can hold down the Fn key and at the same time press on the F5 to switch video between internal and external monitors.
It’s possible the LCD cable got disconnected from the motherboard or LCD screen. You can try reconnecting the video cable on the motherboard and LCD.
It’s hard to troubleshoot this kind of problems without looking at the laptop.
July 7th, 2010 at 10:30 pm
Thanks for very handy instruction.
I love this site for clear structure & clean explanation.
Btw, I’d like to expose my laptop monitor problem :
1. Cause :
I spilt few drops of tea (no sugar) on laptop keyboard & mouse pad.
2. Result :
For few days, my laptop worked well.
Then, hdd dead. LCD is ok.
3. My stupid efforts :
I opened laptop case & saw its inside.
No trace of tea on any parts.
Perfectly clean (My tea was wholy deep brown color).
But while I repacked the laptop case, a metal screw had been lost & found in speaker hole. So I’d been shaking my laptop to get it out.
4. result :
Not only hdd is gone, but LCD too.
LCD appears now dead end.
5. My reasonable efforts :
Replaced dead hdd for new one & laptop Connected to another LCD Monitor for pc.
6. Result :
My laptop works perfect with new hdd via another LCD monitor !!
7. My question :
What’s the problem & solution of my laptop LCD has no sign of life ?
Thanks for reply in advance.
May 1st, 2010 at 11:07 am
Maryann,
Does the problem appear as soon as the laptop is turned on, even before Windows starts loading?
If yes, test the laptop with an external monitor. If video on the external monitor works fine, most likely you have a problem with the laptop screen.