Troubleshooting laptop with backlight failure
This laptop came for repair because of the LCD screen backlight failure. My customer complained that the laptop LCD screen is black but the laptop works with an external monitor.
Here are my steps for troubleshooting this laptop with the backlight failure.
First of all, I tested this laptop with an external monitor connected to the VGA port and the external monitor worked absolutely fine. I was able to get crystal clear image on the external screen even though the internal screen didn’t light up. If the external screen works fine, then most likely there is nothing wrong with the video card.
Notebook display assembly diagram
After that I took a closer look at the laptop LCD and noticed that the screen is not completely black. The laptop screen still works but the image is very very dull, you barely can see it. It means that the screen still gets data signal from the video card, but for some reason the backlight lamp doesn’t work.
From my experience I know that this problem can be related the lid close switch, faulty inverter board or bad backlight lamp. I checked them one by one.
If you have a similar problem, make sure the lid close witch moves freely. The lid switch is a small button located close to the LCD screen. This button triggers the hibernation or sleep mode when the screen is closed. If the lid close switch is dirty, it might get stuck inside the laptop case and cut off the power from the inverter board. The inverter board works as a power supply for the backlight lamp and if there is no power coming to the inverter board, the backlight lamp will not light up either.
In my case the lid button worked properly, it didn’t stuck inside the case. When I was pressing on the button very fast, I was able to light up the screen but only for a fraction of a second. The image wasn’t bright and it had a pinkish tone. A pinkish tone usually indicates a problem with the backlight lamp, not the inverter board.
Even though I suspected the backlight failure, I decided to test this laptop with a new inverter board just in case. But it didn’t help. The screen didn’t light up even after I replace the inverter board. So, I was right, this problem is not related to the inverter board.
Finally, I disconnected the screen backlight lamp connector from the inverter board and connected my test backlight lamp (I removed it from another cracked screen). For the test purpose, you can buy a new backlight lamp here. Try to find a backlight with the connector already attached to it, so you can plug it into the inverter board. Make sure the connector on the backlight lamp is similar to the connector on your LCD screen.
As soon as I turned on the laptop, my backlight lamp lighted up. Yep, that’s the problem. The laptop screen has a faulty backlight lamp.
Here’s another laptop with backlight failure
This laptop video fails in a little bit different way. In this case the backlight lamp hasn’t failed completely.
The laptop starts with video on the screen but the background has reddish tone, the screen flickers and it makes noticeable buzzing noise coming from the backlight and inverter area. After a few minutes the backlight turns off by itself and the buzzing noise stops. When the backlight is off, the image on the screen is still visible but it’s very dark.
I removed the screen bezel and connected my test backlight lamp.
My test backlight works absolutely fine. The lamp doesn’t flicker and there is no buzzing noise. So, this laptop needs a new backlight lamp.
Entry Filed under: LCD Screen Repair
September 7th, 2007 at 7:34 pm
Dude you rock… I did as instructed.. works like a charm… it was only the switch. Thank god but none the less.. my sony is back up and runnin
September 9th, 2007 at 8:12 am
Hey Dude! I have problem with my monitor! My external monitor works fine so it’s possible a problem with back light! I press the lid switch and just for a piece of second turns on as you said so probably the switch has no problem. Sometimes it turns on just for a few seconds so I suppose that there is no problem with thee lamp. So I again uppose that it is a problem with the inverter. Could you tell me how can I open my monitor to change the inverter and an idea on how much this could cost?
Thanks again friend.
Very good post…
September 9th, 2007 at 5:24 pm
Angelos,
You’ll have to remove the LCD bezel as it shown on the pictures. In most cases the screen inverter is located under the screen. All you have to do - unplug cables on both ends of the inverter board and install a new inverter. You can search for a new inverter here.
These laptop disassembly manuals can be useful.
September 11th, 2007 at 11:35 am
Hello… I have a dell latitude CPx laptop wtih the problem you described. The screen is still working but I can see only a very dull image. I do not find the lid close switch where you said it was. There is not any button close to the LCD screen, but the power button. Oh, this problem began when the laptop, into its briefcase,fell to the floor and slightly hit its back. Maybe is anything broken in it, like the backlight lamp or the video cable? I have not opened the laptop.
September 11th, 2007 at 1:49 pm
Wojciech,
It could be just a loose connection on one of the inverter ends. Try reseating these connectors, it might help. Also check connection between the video cable and the motherboard/video card.
You cannot tell with part is failing the inverter board or the backlight lamp without testing the laptop with a known good backlight lamp (or inverter). I think you might have a dead backlight bulb because the laptop was dropped.
Anyways, try reseating cable connections first.
September 21st, 2007 at 7:17 am
Hi, I think my back light inverter may be faulty. I’ve checked it with an external monitor and it’s OK. You can see the image on the laptop but it looks like every other vertical LED is not lit? ie if you look at the letter “S” it would look like a “$” I have a Compaq N800vp, product DJ125T. The question is, can I get a replacement back light or will I have to buy a whole laptop screen?
Yours suggestions would be very much appreciated
September 23rd, 2007 at 1:31 pm
i’ve got a laptop diagnosed and they said i have a bad motherboard due to waterdamage. i want to take out the motherboard and put in a new one. however, rather than just put in the old outdated one, is there another motherboard you reccommend that would fit inside the laptop?? and how much would that run compared to putting an old but working replacement??
September 23rd, 2007 at 9:56 pm
Eugene,
If you still can see the image on the laptop screen then the problem is not related to the inverter board or backlight lamp. When you have a dead inverter or backlight lamp, the whole LCD screen will be dark, not just some vertical lines.
From your description I would assume that you might have a faulty LCD screen. There is a possibility that your problem is related to the video cable.
September 23rd, 2007 at 10:47 pm
Michael,
First, I don’t know the name and model of your laptop. Second, in most cases you cannot upgrade the motherboard.
September 24th, 2007 at 12:34 pm
I have a toshiba satellite M35X-S149 with what appears to be a bad LCD backlight. So i bought a “new” LCD screen to install. However, once I installed the screen, the same thing happened that the last screen was doing. The video would show up VERY faintly and the external video would work, but the backlight would not work. I tried switching inverter boards and nothing helped. I think I may have a grounding problem. I think i’m not putting the black wire with an “eye-hole” at the end in the right spot. Does anyone know where it goes? Please Help!
September 25th, 2007 at 4:19 pm
Hello, I’ve been having to live without my laptop since December 31st of last year because of this problem. I don’t have the money to take it in and am trying to save up to fix it some way. I’m wondering if anyone can help me identify the problem because I’ve read and speculated a few different things.
Last year the LCD light began flickering and I could hear a faint high-pitched noise. If I closed the monitor and re-opened to “wake” it back up, the light would work for a few minutes and then go out again. It eventually went out completely. Now, I can barely (barely!) see the screen (and as of a few minutes ago, for some reason I cannot get a screen at all). I have a desktop at home also, and tried to hook the monitor up to the laptop to no avail. I went through troubleshooting and cannot figure out why the laptop will not comply with the external monitor. I read through your posting and am a bit confused (I’m not good with the hardware aspect, so I’m clueless right now) so I’m hoping you have some insight…
Laptop: Dell Inspiron 5100
External Monitor: MultiMedia Series M70 (ViewSonic M70 on RAGE 128 VR)
Anyone have any ideas? Inverter board? LCD? Something else?
September 27th, 2007 at 3:47 am
Mike,
First of all, check out this page about extended warranty for Satellite M30X, M35X, A70 and A75 laptops. Hurry, this extended warranty ends soon (I believe in November 2007). You might qualify for a free repair if you purchased your laptop in the U.S.A.
If you are asking about a short black wire attached to the video harness, then you don’t have to connect it to anything, just route it alone with the video harness.
So, you’ve replaced the LCD screen and the inverter board but still have no backlight? There might be a problem with the video cable. Also, it’s possible that you have something wrong with the motherboard but I doubt it because you have external video. I would try replacing the video cable next. Did you try reconnecting the video cable on the motherboard, just in case, to make sure it’s making a good contact with the motherboard?
It’s also possible but to find out you’ll have to disassemble the laptop and assemble “outside the laptop case”. Not sure if you want to go this route and I would do it only as a last resort.
September 27th, 2007 at 4:08 am
Shawna,
I think you might have two different problems with your laptop and it’s always hard to troubleshoot any laptop with two or more different issues.
This hight pitched noise and flickering screen could be caused by a faulty inverter board or failing backlight lamp. I would try replacing the inverter board first, you have a better chance to fix this issue. If it doesn’t help, you’ll have to replace the backlight (witch means replacing the LCD screen).
A few days ago I was troubleshooting a Dell Inspiron 600m with a similar problem. In my case the screen was making noise and it flickered as yours, but when the backlight was on, the white colors had reddish tone. I connected my test backlight lamp and it stopped flickering and the noise was gone. So in my case it was a faulty backlight lamp.
When your screen flickered, did you notice that white background had reddish tone? If it was normal white then most likely you have just a faulty inverter board. You’ll need more equipment (as spare backlight lamp or inverter board) to make troubleshooting more accurate.
I don’t like this one. So you had flickering screen/no backlight/faint image for a while and then it disappeared and now you have nothing? Could be a problem with the motherboard, video card, CPU or memory.
I think you should take your laptop to a professional repair shop for diagnostics as you have more then one problem.
October 4th, 2007 at 8:18 am
With the high pitched noise, especially if it’s coming from th elid, I’d suspect the inverter. You might check out the LCD troubleshooting flowchart I’m working on:
http://www.daileyint.com/hmdpc/lcd.htm
I actually popped into this thread to ask if the owner had any feedback on the flowcharts, but couldn’t figure out how to contact him.
Morris
October 5th, 2007 at 12:15 pm
Morris Rosenthal,
I didn’t have chance to go through all troubleshooting charts but I think this is a REALLY GREAT idea.
October 11th, 2007 at 3:50 pm
Before I order the inverter I would like to have one more question that might help if it is the lamp or the inverted. In the begining, before the screen is totaly black(not exactly black but with this shadow), sometimes suddently the light turned on until I switch off the laptop but next time again black. This hapenned for 3-4 times and then all black…This indicates if it is inverter problem or backlight lamp? Thank you…
October 13th, 2007 at 7:50 pm
Angelos,
It can be inverter or backlight lamp. You cannot tell until you test the laptop with a known good inverter or a known good backlight lamp. You’ll have to guess.
You said the screen is black. How black it is? Can you see faint image on the screen?
October 15th, 2007 at 3:02 am
Yes, I can see a little. Especially if it is dark in the room I can see more. Also I am not hearing any noise from inside.
October 16th, 2007 at 8:44 pm
Angelos,
I would try replacing the inverter board first. There is a good chance to fix the problem and it’s way cheaper and easier then replacing the backlight bulb or the LCD screen.
October 22nd, 2007 at 9:34 am
Hey…
I have been having problems with backlight/inverter recently.
After reading up on many websites, i figured i had inverter problem since my lcd was dim to the point where i couldnt see anything. I ordered the inverter from ebay and got it today. After replacing it, i noticed that the laptop works fine for few (2) seconds and then goes dim again. If i tap on the lcd close button, it again turns on for (2) seconds and then goes back dim.
I am not sure what the problem is :S could it be that the backlight is bad or can there be something else?
thanks in advance
October 24th, 2007 at 3:55 am
Finally, I replace my inverter and like previous guy said it worked for 2 seconds with a strange noise from inside and then again the same problem (a faight black image without noise). Maybe this helps about my problem? Thanks again.
Angelos
October 25th, 2007 at 9:10 pm
Dj, Angelos,
If the inverter you installed is good, then my next guess would be the backlight lamp.
October 29th, 2007 at 11:24 pm
Tonight my Thinkpad 600X had a unlit screen.
Last night it was fine.
Backlight lamps look wickedly hard to replace but cheap on ebay. Inverters easier but not cheap. A new LCD, more than the whole laptop is worth.
Your suggestion to check the screen close switch - pure genius! You Rock.
November 2nd, 2007 at 2:23 pm
Can I test a backlight bulb directly after buying without opening the whole screen?I mean can I connect it dirrectly to the inverter without the metal part for testing first and if it works then replace it?
November 4th, 2007 at 10:48 pm
Angelos,
Yes, you can if the bulb comes with wires so you can connect it to the inverter board. The metal part is just a reflector.
November 9th, 2007 at 5:46 pm
I get the buzzing sound coming from the inverter and if I turn the brightness up the screen goes black and the buzzing stops. after it being on for awhile the left side of the lcd is slightly more dim than the right. external monitor works fine. Do you think its an inverter or bulb and if its the bulb where would i find one (inspiron 9400 - true bright screen) i found the inverter on ebay but can’t seem to see any bulbs maybe i’m not searching right. I want to know which it is before i shell out the money thanks
November 17th, 2007 at 4:39 am
Dear all,
I`ve problems with my notebook-screen. It shows a vertical bar, within the bar the image is darker than on the remaining screen.
Does anyone have an idea if this is related to a broken video cable?
Martin
November 25th, 2007 at 10:40 am
I am guessing that there is a cable to the screen problem, my unit works properly using an external crt but even while connected to the crt my laptop screen showes a medium white background with no other images. I can increase or decrease the brightness of the laptop screen using the function keys but still there is no image at all on the laptop screen only a uniform smooth white glow.
E-Machines m5312 laptop about 2 years old
LTN154X1-L03 Samsung LCD
W-720 Inverter
November 25th, 2007 at 6:08 pm
Martin Ruge,
This sounds like a problem with the LCD screen, not with the video cable.
November 25th, 2007 at 6:12 pm
Mark LaTorre,
It’s very possible that there is connection issue between the vide cable and the LCD screen. I’ve seen this problem before. Reseating the video cable might fix the problem. You’ll have to take a look on the back side of the scree, that’s where this connector is located. Make sure the video cable is properly plugged into the connector on the screen.
December 2nd, 2007 at 12:21 pm
So, I have this problem with my Vaio PCG-K33 laptop. How do you remove the screen to replace the backlight lamp?
December 3rd, 2007 at 11:59 pm
Stefana Muller,
Here’s how I removed and disassembled the LCD screen on a Dell notebook. It’s not the same notebook but I can get the idea.
By the way, the backlight is located inside the LCD screen and in order to replace the backlight lamp you’ll have to take it apart. If you have no experience, you can permanently damage the screen.
December 23rd, 2007 at 9:27 am
I’ve been having problems with my backlight too. I have a Toshiba Satellite Pro M40 and the backlight acts strangely. Sometimes it will work fine, other times it will come on after a minute or two, and other times it will come on if I f**k around on the computer’s monitor settings. It has been doing this for about a year but I can always get it working in a few minutes before. But for the last few days it hasn’t turned on at all no matter what I do. I’ve known for quite some time that it was my screen itself because I sometimes have to use a flashlight to see to get to the monitor settings. I don’t plan on taking it apart but I’m grateful to posts like these that can help me pinpoint the problem to tell the repair shop.
January 10th, 2008 at 12:09 pm
I’m working on an Thinkpad A22m (2628-SSU) that was dropped. The LCD is displaying but only very, very faintly. I figured I could do an upper half replacement and ordered one from eBay. So far I have been unable to get the replacement to display anything. The damaged LCD panel is 1400×1050, while the replacement is 1024×768. Could that be the cause of my problems?
January 11th, 2008 at 12:26 am
It could be:
1. Loose connection on the inverter board, you’ll have to reseat cables on both ends.
2. Damaged backlight lamp (CCFL), in this case you’ll have to either replace the lamp (no easy) or replace the whole LCD screen (much easier but more expensive).
3. It’s possible that the inverter is dead but most likely you’ve damaged the backlight lamp.
Unfortunately, the only reliable to find the culprit is testing the laptop with another working screen.
January 11th, 2008 at 12:43 am
Bahula Smith,
What do you mean by upper half, the whole display assembly with LCD, cable and inverter or just the LCD screen?
January 11th, 2008 at 4:42 am
cj2600,
Yes, I purchased the whole LCD assembly. Lcd panel, inverter, cable, bezel, etc. I can’t get anything to display at all on the new assembly. I’ve tried changing several BIOS settings thinking that could be the problem, but still no joy!
BTW, what could be the problem with the old display? I am guessing since it was dropped that it is the bulb. The LCD panel is not cracked and still displays (although very darkly).
January 11th, 2008 at 8:27 am
Bahula Smith,
First or all, check the lid close switch. It’s possible that the switch got stuck inside. Try tapping on the switch with a screwdriver, make sure it moves freely.
Second, it could be loose cable on the inverter board. I would try reseating cable connectors on both ends. I think it worth trying.
I would suspect the lamp failure too, I don’t think that you can damage the inverter by dropping the laptop.
January 15th, 2008 at 4:14 am
cj2600,
Lid close switch = ok
Inverter connections = ok
Still a dim display…
So back to the LCD assembly that I purchased that will not display anything, 1) it could be bad, 2) I could be doing something wrong… although I’m not sure what, or 3) it could be incompatible. Now that I think about it, it makes sense that the output from the video card needs to match the LCD panel. Will a 1024×768 panel work where a 1400×1050 once was? Thanks for the help.
January 19th, 2008 at 8:12 am
Hey there!
I am the owner of a Toshiba Satellite 5200-902.
The first weird behavior I noticed was the pinkish colors when my screen was just turned on and the colors were normal after a few seconds. I don’t remeber when was this behavior started, but I think it is at least for the last 2-3 months.
During the last week I had a flickering problem with my LCD screen.
Please check the following short video to see what I mean: http://video.google.com/videoplay?docid=4545062325473598117
Sometimes, I could hear a whistling sound too!
My graphic card seemed to be ok since I could connect an external monitor and have no flickering to the external monitor.
So, it should be a problem with one or more LCD parts…
Since yesterday my screen turned almost totally black! I can hardly see the desktop.
However, the flickering seems to have stopped and I can still connect with an external monitor.
Do you have any idea what is that could be going wrong with my LCD?
I think there the following possibilities:
1. The problem is complex so the whole LCD needs replacement
2. The video cable needs replacement
3. The inverter that supplies the power needs replacement
4. The backlight bulb needs replacement
5. The inverter or backlight cable needs replacement
6. Other (please specify)
Please if you are familiar with my problem I would appreciate your help.
Thank you for your time reading my problem.
Andreas
January 19th, 2008 at 1:46 pm
Bahula Smith,
I think it will but I’m not sure 100%. I don’t work a lot with IBM laptops.
Here’s what you can try for testing the backlight lamp inside the new LCD screen.
Disconnect the LCD screen on your laptop from the inverter board and plug the new screen instead. In this setup the video signal still goes to the old screen and you still should see a faint image on the old screen, but the inverter board will provide power for the backlight lamp inside the new screen. If the lamp inside the new screen is good, it should light up (I assume the inverter board is working fine).
Check out if you can light up the backlight lamp inside the new screen.
January 22nd, 2008 at 9:16 pm
Hi,
I have a Dell Inspiron 9200 and the LCD display is extremely faint:
I can see a very faint image so think I don’t have a working backlight in the LCD display.
I can plug in an external VGA screen and it works well
I purchased from ebay a new display/inverter/cable and it still is has a very faint image.
I noticed the LCD plugged into the ATI video card (while the VGA plugged into the motherboard) so got a videocard on ebay; same issue.
So I have replaced everything but the motherboard. Are there special voltages the inverter needs to enable the backlight?
I don’t see the on off switch for this computer and a google search didn’t help yet either. Do you know where the on/off switch is? I would think the computer would go into hibernate mode if this was an issue.
Any other ideas of where to go next? I am pretty hardware/computer proficient but very frustrated with this issue.
Thanks,
Mike
January 22nd, 2008 at 11:05 pm
Mike D,
Did you buy and swapped the whole display assembly or you bought all parts one by one? Did you try replacing parts one by one? First inverter, then LCD and finally the video cable.
January 30th, 2008 at 3:49 am
cj2600 do you know what is the input-output voltage characteristics of any of the inverters:
G71C00011121 (toshiba part number: P000354880)
or
G71C00011221 (toshiba part number: P000439470)
Thanx in advance!
January 31st, 2008 at 8:34 pm
Andreas,
I don’t know. Toshiba doesn’t provide this information and I’ve never tried measuring it myself.
February 1st, 2008 at 12:28 am
Thanx cj2600…
I used an AC multimeter to measure the output of the inverter while the input was normally connected to the laptop.
The output was more than 1000V AC!
This means that the inverter works (since it is supposed to have a high voltage AC output) and this is what I call bad news.
Since the inverter works my only solution is to buy a new LCD screen?
Right?
Could something else be wrong?
Toshiba service replaces the LCD with 940 euros!!!!! Of course this is not an option, I better buy a new laptop. On ebay the price is much better, around 200 euros but then I am worrying if the screen will be ok after doing the long trip from USA or China to Greece.
If there is no other case for something to test if it is not working then probably I will have to risk it…
Please suggest me if I should check another part before ordering the new LCD.
Thanx in advance!
Andreas
February 21st, 2008 at 4:50 pm
[…] problem still could be related to the screen backlight. Unfortunately, the only way to find out is testing the laptop with another working backlight attached. Try reducing the screen brightness a little bit, it might […]
February 24th, 2008 at 12:12 pm
At last!
I fixed my LCD!
I found some backlight bulbs from the LCDs of old laptops that were sent for recycle!!!
I made the appropriate connections, I re-assembled my LCD and everything worked fine!!!!!!!!!!!
February 26th, 2008 at 10:31 pm
Am I correct in assuming it isn’t the inverter, backlight or cable if I get no power to the screen, and nothing on an external monitor?
My display failed on my A70 after disassembling due to the overheating issue. Laptop powers on, hd fires up, no beeps, just no display. Reseated inverter wires, ground and video on the board…still nothing. Took it all apart (again), reseated the CPU and heatsink….still nothing.
Any ideas for troubleshooting? I’m really stumped! Thanks
February 28th, 2008 at 6:53 am
OK… I think I have a good little problem for someone to try to solve. My laptop backlight wont light up. Everything works and looks great when I send the video to an external monitor (my TV). I can also see the picture on the laptop monitor if I look closely and use a flashlight. I replace the inverter board… didnt fix it. I took the lcd apart and I have a new backlight as well as the old backlight resting comfortably outside the lcd panel so that I can see it clearly. Here is what I see. Please Help. When I turn the laptop on, the backlight flashes once real quick, and thats all I get. I don’t know if the inverter I put in there is just another bad inverter board or if this is some sort of power supply issue or something else. Please Help
March 4th, 2008 at 10:15 am
The LCD panel on my IBM ThinkPad T60 (model #1953-D9U) got cracked, but with the exception of a small 2″ square area where the damage occurred (white screen), I could still use the laptop with the screen open.
However, now that I have tried to replace the screen with a new one, I cannot get the new screen or the old one to light up. I thought I may have damaged the inverter, so I bought a new one and installed it. However, I am still not getting power from the inverter to the new LCD (no backlight) and the images on my old screen are very faint…as if it was a bad inverter. (FYI - The external video still works perfectly.)
I have not tried to replace the LCD cable yet (perhaps I damaged it when removing the old one?), because I am trying to find out where the “closed lid” switch would be on this model. (My old T30 had a mechanical switch that could be depressed, but this one doesn’t.)
Please tell me the best approach for troubleshooting this problem, and if it sounds like I may need to take or send it to a laptop repair shop. Thanks.
March 5th, 2008 at 10:02 am
to 51 (Roy)
I thought I had a bad inverter so I bought one on ebay… guaranteed not to be DOA. It did not fix my problem. After thinking and scratching my head for a bit, I decided that the issue was still the inverter. I bought another one and this one fixed my problem. What is the point of this story? Well it is simply where did you get your inverter? and how can you be sure that this replacement part is in working condition? After all the one I bought was guaranteed to be NOT DOA but it was in fact DOA.
Your best bet is to try again or find someone with the same model that is working and try their inverter.
March 5th, 2008 at 12:40 pm
Thanks for the tip, Brad. I bought the inverter “new” directly from IBM/Lenovo, but I suppose it could be bad. However, since this was my first crack at fixing a laptop, I am more inclined to think I damaged the cable or (worse) something on the system board, because I forgot to take the battery out first. (Doh!)
March 6th, 2008 at 7:30 pm
Roy,
Let’s assume that both new parts LCD and inverter are supposedly good. Here’s what you can try in order to troubleshoot the problem.
Let’s say you have the new LCD screen installed. Leave the data cable connected to the back of the screen but disconnect the cable witch goes to the inverter board and plug the old LCD screen instead. In this combination you still should see a very faint image on the new(installed) screen but the inverter board should light up the backlight inside the old screen. If there is no backlight, swap the inverter board and try again.
After that install the old screen back into the laptop. Connect the data cable into the slot on the back of the LCD, but plug the new screen into the inverter instead. In this combination you’ll get image on the old screen but the backlight will be on the new screen. If no backlight, try swapping inverters.
Also, you may try connecting LCD and inverter without mounting them inside the display panel case, maybe it’s grounding somewhere and will work outside the case.
If you still cannot get the backlight and your parts are supposedly good, apparently there is a problem either with the video cable or with the motherboard. Just in case check connection between the video cable and the motherboard located under the keyboard, maybe you accidentally pulled the cable.
If you cannot see the lid close switch, apparently it’s a magnetic one and located somewhere inside the laptop case. I don’t think this is your problem.
March 15th, 2008 at 12:39 pm
I am having trouble with my satellite m35x-s111 lcd display. I can see the whole image, but the lcd brightness is very low. I also noticed that brightness is higher in the right side of the display. How can i know if the trouble is in the inverter module or in the backlight lamp? The lamp can be easily replaced? Thank you.
March 15th, 2008 at 2:31 pm
Guillermo,
1. Could be bad inverter. Maybe it’s not providing enough power to light up the backlight.
2. Could be a faulty backlight.
Unfortunately, I cannot tell you witch one is causing the problem. You’ll have to test the laptop either with another working inverter or another working backlight lamp.
It’s not easy to replace the backlight lamp because it’s located inside the LCD screen. You’ll have to take apart the screen. You can easily damage the screen if you have on experience with fixing laptops.
March 17th, 2008 at 11:20 am
Hi there,
myToshiba M70-215 has faint light, i had taken to repair, they tried invertor and couldnt repaired. Now they take to far away for repair and send computer for that reason. The laptop works fine w/ external monitor, and vision on original screen is very faint , can be seen on very light environment. So i dont think my screen went totally off. However, the repairment men from where my computer send gave us estimated repair demage and cost claiming that LCD screen went off and screen need to be replaced and sure that cost 250 USD. I am having hard time to belive ( since laptop is not older than 2.5 years just after waranty end!!) that and never dropped, that screen went out. Ithey just wanted to suck me i have strong belive right now it is backlight lamb and not invertor.
As an expert would you confir me that if screen went off i would never get any vision on screen right ( besides i used to have loss of light or brightnes while computer works few months aga, any time i turn off computer then light was comming on scree. The final and resisting light loss happened while i am using computer, the vision sudenly gone, and screen can be hardly seen with carefull look. So just give me some expert information before i decide replace my LCD screen. Do you think it need to replace LCD screen or light bulb. We tested inverter by bringing new inverter from Toshiba but didint work.
with my best regards from Turkey
haluk testereci
March 17th, 2008 at 11:30 am
Hi ( Ref 57)
In addition of my question on 57
would that be reason hard to replace light bulb ofr Toshiba M70-215 screen, so they might be asking for whole LCD replacement ? Is it easy to replace light back bulb, and what is the aproximate cost on that lamb?. Is there any visiual show of that light bulb might be?
thx for any help
best regards
haluk testereci
March 18th, 2008 at 2:21 am
response 57 &58
I found out that repairmen is trying to sell me whole LCS screen. It is only problem is backlight lamb and since they dont carry the lamb he wants to sell me whole LCD secren w/lamb..So iwas right on. Besides same attitue Toshibe center has, they want to sell whole LCD screen for about USD500 when i told only backlight need to replace as other repairment diagnosed at distance, Toshiba center is even unaware or pretending as unaware there is even backlight lamb…so kind of ridiculus bussines going on here. Now i am going to on my own, try to collect proper lamb and fix it w/ myself or fix w/TV repari man who would do things more chepaer…
any help on where to fing backlight lamb and instruction to fix that would be helpfull
regards
haluk
March 19th, 2008 at 9:20 pm
Haluk testereci,
If a known good inverter didn’t fix the problem and the image on LCD screen is still very faint, most likely you have a problem with the backlight lamp (CCFL) inside the LCD screen.
It’s not easy to replace the backlight lamp because you’ll have to take apart the LCD screen. Most repair centers will not replace the backlight lamp, they will swap the whole LCD screen.
Here’s an example how to replace the backlight lamp.
March 25th, 2008 at 5:48 pm
I Don’t think my screen problem is related to an inverter or a backlight. When I fire up the computer my screen flickers and depending on how I move the screen up and down it gets better/worse. I have a 1.5″ area top to bottom on Left hand side which remains uneffected but the rest of the screen is distorted. I took it apart and when I tap the top back of the screen with my finger it replicates the problem. This area is near the cable and the Green circuit board.
March 26th, 2008 at 8:53 pm
Frank,
This is not related to inverter or backlight.
To me this sounds like a problem with the LCD screen itself.
Take a look at this post. You screen looks similar to examples 5 and 9, right?
April 12th, 2008 at 8:38 am
I’ve got Toshiba M70 with a slightly different screen problem. Everything works fine on an external monitor but with the laptop screen, at first it appears the screen is dead. The screen remains black when booting up, but if you look closely, it is noticable that there is light behind the screen, I just wasn’t getting an image. I started poking around and found that if I squeezed the top left corner of the screen, I got a nice bright image and the computer was working fine, my thumb gets really tired while surfing though. It has to be some sort of connection problem, but I just can’t find it.
Any idea’s?
April 16th, 2008 at 1:26 pm
it songs good so i am going to try it to see if it work on my dell laptop.
thank you.
May 1st, 2008 at 11:32 am
I am having LCD issues with a Dell Inspiron 6000 laptop. I have replaced the inverter initially, and tried replacing the bulb with no success. There is still a ghost image on the original screen, and the laptop works fine with an external monitor attached. I finally broke down and got an aftermarket LCD screen, which works but is very
dim compared to the original. When I check display settings it lists only “multiple monitor” configurations and I can’t seem to find a way to reset to just the built-in monitor. It has an ATI graphics card which supports and changes multiple monitor settings, and under devices there is a “mirror” monitor device also. Any ideas whether
going to single monitor configuration will allow adjustment to a brighter screen setting, or could cabling or motherboard issues
be involved? Thanks for any help.
Ken Cotton
May 3rd, 2008 at 7:19 am
my laptop Aspire acer 7620 bios setup was passworded by my younger brother, And he has forgoten d password and operating on d laptop as corrupted,and there is nothing i can do than to boot to the cmos setup and setup the boot option to load another operating system.and have tried all the master password that i know none of it solve the problem .now i dont know what to do either to go for a new laptop or i should try other site for help.please if anyone can solve my problem i promise to be his or her friend forever.i also i’m an engineer and i’m fed up with it.THANKS.MY LAPTOP IS A PHOENIX MAKER.
June 14th, 2008 at 5:34 pm
[…] First of all, take a closer look at the LCD screen. Look at the screen under bright light. It’s possible that the image is still on the screen but it’s very faint. If that’s the case, check out these tips for troubleshooting laptop with backlight failure. […]
July 8th, 2008 at 11:48 pm
I had severalo keybord keys that weren’t working
missing letters and keys that don’t work:
eghikmopruw
up & left arrow
rt ctrl
\|
delte end home
pg up pg dn
5 6 - _ =+
num lk
i also managed to, idiot that i am, pull the LED cable along with the part it plugs into right off the system board. Please help screen is almost too dark to see. and with the keyboard problems i can’t perform fn up to brighten it up if that would even work with the led cable inoperative.
thank you for ANY help.
July 21st, 2008 at 5:06 am
My problem sounds very similar … when i press the Lid close switch and then release it, the light comes back and the screen is well lite but only for a few seconds. it doesnt seem to be the backlight since when it does lite up it looks as usuall.
what should i do..?
July 22nd, 2008 at 1:25 pm
shanron zusman,
1. Replace the inverter board and most likely it will fix your laptop.
2. If you still have the same problem, probably the backlight lamp is bad. If that’s the case, you’ll have to replace the LCD screen. It’s possible to replace the backlight lamp inside the screen but it’s not easy.
July 28th, 2008 at 7:13 pm
My Dell laptop went black today, after flickering just a bit for the last week or so. From everything I’ve read, I’m thinking it is the inverter since it works with external monitor and it actually lit up once when I brought it out of the screensaver mode. I talked to the Dell tech support and finally got the guy to tell me one of the tests to try. It sounds crazy, but he said if you turn it upside down and then power up, if the screen lights up you know it’s not the backlight, so it’s likely the inverter.
Well, I didn’t power down, but closed the lid so it went to standby. I turned it upside down and then opened it and voila! the screen looked normal. The one thing I still wonder about is something I read about a failing backlight causing the inverter to shut itself down. That scenario isn’t proven or disproven with my test. So I guess I’ll get a cheap inverter and see what happens.
July 29th, 2008 at 10:26 pm
Joy,
That’s interesting! I’ve never heard about this test. I’ll try it on different laptops with inverter/backlight failures.
July 30th, 2008 at 10:44 am
I had the same issue with the backlinght very dim on the lcd screen on a dell laptop. So I replaced the inverter but it had the same issue, then I went ahead and replaced the entire lcd screen with inverter and backlight and still had the same issue, so I tried moving the motherboard to another laptop and still had the same issue so I just replaced the motherboard and that worked.
July 30th, 2008 at 12:29 pm
Fernando,
It happened to me before. In some cases the problem looks like bad inverter/backlight lamp, but it’s bad motherboard.
That’s why I always test a faulty laptop with known good inverter and backlight lamp before I jump to a conclusion.
August 7th, 2008 at 7:56 pm
Unfortunately, replacing the inverter didn’t fix my problem. I’ve gotten a replacement backlight, but it doesn’t have connectors as it was advertised, so I have to solder it. Since the inverter I bought was refurbished, I wondered what are the odds I got a faulty one?
Since I now have 2 inverters and 2 backlights, I should be able to test different combinations, but I only have one set of wires so it’s more difficult…
August 16th, 2008 at 6:58 pm
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August 17th, 2008 at 6:30 pm
My laptop frequently have just a blue/gray screen when I
boot up. I’ve tried every thing I can, but it doesn’t work. Any suggestions?