Screen backlight lamp
A backlight lamp (also know as backlight bulb, screen backlight, CCFL tube or bulb) is the main and only source of light in a laptop LCD screen. A typical laptop LCD screen has only one backlight lamp installed. The backlight lamp mounts inside the laptop screen in the lower part of the screen as it outlined on the picture above.
A pair of cables with one connector coming from the screen plugs into the screen inverter board.
The backlight lamp receives high voltage AC power from the screen inverter board which receives low voltage DC power from the motherboard via the LCD screen cable as it shown on the picture below.
On the next picture you see a typical backlight lamp removed from a typical laptop LCD screen. There are two cables soldered to both sides of the backlight lamp attached to one connector.
BACKLIGHT LAMP REPLACEMENT
It is possible to replace a failed backlight lamp with a new one but it’s not easy because the backlight lamp is buried deep inside the LCD screen and it’s very easy to damage the screen during the disassembly process. This repair should be performed only by an experienced technician. You can find some home made backlight replacement instructions if you do this Google search. For inexperienced people it would be much easier to replace the whole LCD screen.
BACKLIGHT LAMP FAILURE SYMPTOMS
1. The laptop screen lights up only for a short period of time or will not light up at all. The image on the screen is so dim that you can barely see it. At the same time, an external monitor attached to the laptop works fine.
2. When you turn on the laptop, the screen works fine for a while, then start flickering and the light turns off. Again, there is a very faint image on the laptop screen and external video output works fine.
3. The screen works but the image has a reddish/pink tone. External video output works fine.
The backlight lamp failure symptoms are very similar to the inverter board failure symptoms. If you have to guess which one is causing the problem, try replacing the inverter board first.
Need spare parts for your laptop?
If you are looking for spare parts for your laptop you can find brand new and used parts here. Just search by the part name and laptop model.
December 4th, 2009 at 2:55 pm
Hi there ,I have a dv2000 , i ready change a new screen inverter,bu screen do not light up, can someone tell me why , I been reading about this here apparently could be the back light,can you please tell me , whats going up
November 30th, 2009 at 7:28 pm
Maryan,
If the screen is cracked, you cannot fix it. The whole screen has to be replaced.
The following guide explains how to remove and replaced damaged LCD screen in an HP Pavilion dv2000 notebook.
http://www.insidemylaptop.com/replaced-damaged-lcd-screen-in-hp-pavilion-dv2000-notebook/
November 30th, 2009 at 4:51 pm
my hp pavillion dv2000 has a cracked lCD. most of the screen has a black and white stains, with line all over. However, a little part if the screen about 10% of it is intact and i can view the actual computer screen on it what do you advise i do?
November 26th, 2009 at 2:19 pm
Jennifer,
It’s possible that one of the cables inside the display panel got disconnected when the laptop was dropped.
Before replacing anything, I would try:
1. Reseating the video cable connector on the motherboard. This connector is located under the keyboard bezel, close to the left hinge. Here’s the guide for removing the keyboard bezel: http://www.insidemylaptop.com/take-apart-hp-pavilion-dv6000-laptop/
The video cable connector is shown on the last picture, but it’s hard to see because of the white sticker glued to the cable. By the way, it’s not necessary to disconnect the keyboard from the motherboard, simply turn it upside down and place on the palm rest.
2. Try reseating connector on both sides of the inverter board. One of them could be loose. This guide explains how to disassemble the display panel: http://www.insidemylaptop.com/remove-replace-lcd-screen-inverter-hp-pavilion-dv6000-laptop/
3. Finally, try reseating the video cable connection on the back of the LCD screen. Same guide as in the step 2.
All these requires laptop disassembly, so proceed on your own risk. You can damage the laptop by doing that if you have no experience.
November 26th, 2009 at 1:39 pm
paul,
I think this is the backlight lamp failure. Apparently the lamp is failing and has to be replaced. It’s hard to replace the lamp, so think about replacing the entire LCD screen.
Just in case, you can try reseating connectors on the inverter board. It’s possible that one of the connectors is loose and the inverter or backlight lamp is not getting enough power from the motherboard. Just a guess.
November 25th, 2009 at 9:15 am
My HP dv6000’s screen just stopped working. I have it hooked up to an external monitor and it works fine. The laptop screen just remains off when i turn it on (without the external display). I don’t know what’s wrong with it. I was sitting on the couch with it on my lap and someone bumped into it and it fell on the carpet. And after that it was working fine. Then i turned it off as usual and when i turned it bk on, the screen never came back.
DO you think it’s a backlight lamp issue? If so, is it a good idea to have it replaced? I talked to HP and they had no idea what was wrong and told me to replace the whole display…which would cost me $350 and it seemed stupid to do that.
Let me know what you think please!
Thanks!
November 22nd, 2009 at 5:24 pm
hi,
only the lower right portion of my laptop screen lights up and after a second or two the screen start to dim until you can’t barely see the image on the screen and when you close the screen and open it up again same thing happens. which could be the problem, the inverter or the backlight. please help..
November 7th, 2009 at 10:16 pm
Ernest,
1. A stuck lid close switch. Make sure the lid close switch moves freely.
2. Bad video cable. It’s not likely but possible.
In cases like that I replace the motherboard. I don’t work on the component level and cannot fix a failed motherboard.
November 7th, 2009 at 9:39 pm
Hi,
If the backlight and inverter tested ok, please what might be the cause of dim on my laptop screen. If the motherboard how would i solve it. Thank you.
October 10th, 2009 at 11:10 am
binu,
Sounds like a software related problem. I think your laptop screen starts working only after Vista logo because the laptop “thinks” the laptop screen is the secondary screen, not the primary.
1. Can you access BIOS screen on the external monitor? Enter the BIOS setup menu and load default settings. Also, find out if you can set the laptop screen as the primary one in the BIOS menu.
2. Boot your laptop to the desktop and go to the display settings. In the display settings you’ll see two monitors. Number 1 and number 2. Click on the number 2. Below you’ll see “This is my main monitor” box. If it checked, uncheck the box, safe settings and reboot the laptop.
3. Start your laptop with an external monitor. Hold down the Fn key and press on the F5 key until video appears only on the laptop screen. Try rebooting the laptop now.
You didn’t have to replace anything. I think your problem is software related.
October 3rd, 2009 at 6:58 am
hello repair man
my toshiba laptop wont display anything on POST. Display will show up after vista logo. everythings fine after vista logo. During POST CCFL lights up for a second and will go off. It will light up again from vista logo. Because of this i cant access the bios screen. I just replaced the lcd screen and inverter but still problem persist. Is it because of the lcd video cable?
if i uninstall the video driver ccfl wont light up at all. Then i had to plug my external display to install driver then it will start from vista logo.
August 19th, 2009 at 8:20 pm
Guido,
Sorry, I do not understand your question. Maybe I’m missing something?
August 18th, 2009 at 1:10 am
Dear Repair man,
Im trying to find out what the differences between LCD laptop panels and LCD monitor panels are.. Could you help me on this one?
Cheers,
Guido
July 28th, 2009 at 4:36 am
I just replaced the backlight bulb in my Compaq v2000. It now gets very hot down where the bulb is and shuts off after a few hours. What could be causing this and how would I fix it? Thanks!!!
July 26th, 2009 at 11:37 pm
hey repair man,
thanks for the super quick reply!
i already tried plugging the new monitor into the original inverter, but it didnt work. the screen shows up for the loading screen then quickly becomes very faint, which must mean it isnt getting enough power. that would make sense, i assume, since only half the power is being supplied.
the original screen had two backlight connectors which connected to a two-pronged inverter. since i bought the wrong screen, which only has one connector, would it work if i just bought a new one-pronged inverter?
in other words, does the laptop recognize that the lcd is a two lamp screen? or is the inverter the only reason why the two screens have differing numbers of converters?
July 25th, 2009 at 9:31 pm
Bryan,
Apparently you bought a wrong screen. Your old screen has two backlight lamps (not very common for laptops). I would suggest buying an exact copy of the old screen.
I’m not sure about that. I’ve seen very few laptop screens with two backlight lamps.
You can try using your new screen with the old inverter but I don’t know if it will work at all. It either will not be as bright as before (because you are using only one backlight) or the backlight will not start at all (because the inverter has to be loaded by two lamps).