Here are some tips and tricks for troubleshooting and fixing laptop video problems. Video issues are very common within portable computers and with the following tips you should be able to detect and eliminate basic laptop video problems.
Laptop LCD screen has a faint image.
Look at the LCD screen very closely and check if you can see a faint image on the screen. It’s possible that the LCD lid close switch stuck in the “closed” position and the backlight stays off even when you open the LCD screen or turn on the laptop. The switch turns off the backlight when you close the LCD display to save the laptop battery power. Check the LCD lid close switch. Usually it is a small plastic pin located close to the LCD hinges. Try to tap on the switch a few times to turn on the backlight. If after tapping on the LCD lid close switch the backlight stays on, you fixed the problem.
It is also possible that after tapping on the LCD lid close switch the backlight works fine, you see a normal video on the screen for some time and then the backlight turns itself off again. In this case I would blame the FL inverter board. Try to reseat cables on both end of the FL inverter to make a better contact between the cables and the FL inverter board. If it doesn’t help I would try to replace the FL inverter board.
Laptop LCD screen is solid white color.
Most likely it is just a bad connection between the LCD display and the system board. I would try reseating the video cable connector on the back of the LCD screen first and check if it fixes the problem. After that I would try reseating the video cable connector on the system board. I would also try reseating cables if there is no video on the LCD screen at all.
The video on the LCD screen is garbled.
Try to connect the LCD screen to an external monitor. If the external video is fine, you have a problem with the LCD screen or the LCD video cable. You can try to fix the problem by reseating the video cable on the back of the LCD and on the system board.
If you see the same garbled video output on the external monitor most likely it is not the LCD screen problem. In this case the system board (with onboard video) is bad or the video card is bad.
I understand that these tips will not cover all video problems with portable computers. If you have a different problem, you are welcome to leave a comment and I will try to help you if I can. 
Are you looking for a new LCD screen for you laptop? Try searching here.
Here’s a notebook display assembly diagram and tips for finding spare notebook parts.
Related articles:
How I took apart and repaired my notebook LCD screen with water damage
Screen inverter replacement. Fixing laptop backlight problem
Laptop has bad video on the LCD screen. What is wrong?
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May 24th, 2006 at 7:29 am
Wow, I was thinking on the right path for Carlos’ laptop
Maybe i should get into laptop repair also lol.
Any way, the connector for the bulb is a little bit bigger, but i would think that i could solder wires directly on the junker one (just more stuff missing lol). I would think that most inverters would be the same voltage, also i will try to get a good reading on the inverter that might be bad, im hopeing its just that switch so i can just do a quick solder fix, but if i have to put more money into it i guess i should make it right. Thanks a lot for your help so far
.
Also i forgot to tell you about the other things, it does have the very dim immage (ibm logo is about all i can ever make out, but i know it loads to windows). I have another mother board here, but i got error 192 (fan error) with it and that was before the light went out (geting my $150 back from that thing).
I might have to do some research on FLs and FL inverters, my dad has a ton of FL fixturs that i could “hack” apart and make it where the small bulb could plug into it (right polarity of course, if it matters). That is where my multimeter might come in handy
. Im off to fix this and that so i will check back here later.
cmd19872002
May 23rd, 2006 at 8:13 pm
Hey Carlos,
I agree with Cory. The external monitor has a normal video output, so most likely the system board (video card) is fine. I would suspect the LCD screen itself.
May 23rd, 2006 at 8:05 pm
Hey Cory,
First of all, did you replace the motherboard? Is it possible that you got a bad motherboard?
If the FL inverter is bad then you can get the backlight working for a while on start up or it will not light up at all, not for a second. Both variants are possible. But you should have a faint image on the screen if it is the FL inverter problem. Sometimes it’s very hard to see any image, but it still should be there. With IBM laptops you usually can see IBM logo on startup (very faint). The video on an external monitor should be fine, hook it up and check the video just in case.
Toshiba says that you can test the FL inverter with a multimeter. The voltage on the exit from the FL inverter board should be 200-600 VAC. I have never tried to measure it myself and I don’t know if this numbers are accurate. I guess you can measure the voltage on the exit from the FL inverter board to see if you have any output at all.
For test I have 2 different backlight bulbs with different connectors, they were removed from cracked LCD screens. If I see a problem with the backlight, I disconnect the LCD screen from the FL inverter and connect my test backlight lamp. If I still have no backlight then the LCD screen is not my problem and most likely the inverter is bad. If I was able to light up my test backlight lamp, them most likely the backlight on the LCD screen is bad.
You can open one of yours laptops to check if the connector for FL inverter board is the same as on the laptop you are trying to fix. If it is the same connector, you can try to connect your screen to the laptop you are fixing and see if you can get the backlight. It is not necessary to connect the data cable, only the cable for the FL inverter would be enough. If you still cannot get the backlight, them most likely the inverter is bad.
I had a situation very similar to yours. I had to replace the LCD cover on IBM laptop because it was cracked around hinges. After I replaced the cover, the laptop booted without any backlight, it even didn’t turn on for a millisecond. There was a very faint image on the screen. LEDs on the FL inverter board worked fine. I connected my test backlight bulb and it didn’t light up. The problem was fixed by replacing the FL inverter board.
May 23rd, 2006 at 12:18 pm
HI Carlos,
Im no pro with laptops, but if i was asked, i would say the LCD screen, I think if the wire was bad, the screen would have more than 1 line in it. But dont hold me to my word, wait for cj2600, thats the pro
.
May 23rd, 2006 at 8:49 am
Please help! My name is Carlos.
I have also a very thin vertical cyan line in my display. I have tested plugging my computer on a external monitor and it disapears. Does anybody now what would be the most accurate problem? Should I consider: 1.Display hardware LCD problem? 2. Display cable (motherboard to display)? 3. Motherbaord problem?
I ask for any help since I’m living in Brazil and technical opinions are welcome before I go to any costumer support over here.
Any help will be fine.
May 23rd, 2006 at 5:27 am
Opps, sorry about the double post, but forgot, on the inverter board there is the lights for the power/suspend, and they do light up, so i do know that the board is geting somewhat power.
Thanks again,
cmd19872002
May 23rd, 2006 at 5:24 am
Hi,
I have read around 30 posts, and didnt see a problem that was exactly like mine, but here it is:
I get no backlight at all, i have checked the lid switch and taped and did every thing i can to it (i work with ps2s, and i know how them switches can be). Any way, it did work this morning, it just went out (just fixed the mother board
, new security chip. i have reseated the connections a few times and still nothing. I did not bend the lcd or any thing that i know of where the back pannel of the lcd would be broken (i cant see any cracks or any thing either).
Of what i read, if there is a backlight for a bit, then goes out, its the inverter, can it just not work at all and be it?
also the backpannel bulb, its flourscent light, and normaly dont just blow like a bulb in a house, but can it durning power up?
Also is there any kind of ways to test the inverter/backpannel to find what is the problem, or to actaully know that they are working right, but something is not connected?
Such as reading the AC voltage on the inverter to the bulb (probley not but just a ex.) Also i have some older thinkpads here (mines a T30) and i know that they have working inverters and bulbs, can i use one of them (maybe some soldering) to just use as a test, maybe pernament. They are the 365XD model (both are).
* I might take the backpannel apart and check the wires to the bulb to see if it has any beaks, them are too small of wires for my likeing
. but thats probley a few days later.
Like i kind of metioned, i fix ps2s/xboxes and other small electonics just about every day, also modding them, so i have a pretty good hand at soldering/working with electronics. If you want, you can do a google serch for “cmd19872002″ for some of my history
.
Thank you very much for your time (i use to help people online all the time and i know it kind of gets tiresome answering questions for nothing, but in the end its worth it
.
cmd19872002
Email: PS2fixer(AT)Gmail.com
May 21st, 2006 at 12:26 pm
Hey John,
) and reseat cables on the FL inverter board first. If it doesn’t help, replace the inverter board. I think you have good chances to fix your laptop by replacing the inverter board.
In your case I would suspect a bad FL inverter board. If the display backlight sometimes comes back, then apparently the screen backlight bulb is fine. You can remove the LCD mask (I hate removing the mask from IBM screens
May 21st, 2006 at 12:16 pm
Eugene,
You say that a gentle tapping can help you to get the backlight back. I would suggest reseating connectors on the FL inverter board, even though it’s only a guess. Also check if there is a BIOS update. It is possible that there is a fix for video problems in new BIOS release. I’ve never seen a problem like yours before. Usually if a piece of hardware fails it doesn’t matter what application you use.
May 21st, 2006 at 12:04 pm
Charlie,
If you see only a faint image on the screen, then most likely the FL inverter board is bad and has to be replaced. Also, it is possible that the LCD screen backlight bulb is bad itself or the video cable is bad (not very likely). It is hard to say witch part is causing the problem. I usually install a test FL inverter board to see if it fixes the problem.
I cannot say why your laptop beeps without looking at it. There might be many different problems.