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Laptop LCD screen backlight turns off after 5 seconds

The backlight for the screen switches on correctly when the computer is turned on from cold boot or sleep mode or fn-F5 to change monitors. The backlight stays on for 5 seconds and switches off. I have replaced the inverter and screen with the same fault present. I have ruled out the lid switch (it was a hall effect diode triggered by a magnet on the lid) as this works correctly. If I unplug the input to the inverter and plug it back in, the screen comes on for 5 seconds. I can repeat this indefinitely with the time remaining 5 seconds. If it was a heat related issue, the time should decrease. Also the video card appears correct as there is still a picture on the screen and I am using an external monitor. This fault is the same when in the BIOS. I have been through all the settings in both the BIOS and device manager and every thing appears OK and also I am fully protected from viruses (Trend Micro). I have reseated every connection and board on the motherboard. I am now out of ideas. Short of replacing the motherboard which there is still no guarantee that this will fix it either. Thanks in advance.

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  • Master
  • 663 Answers

Hello,
Have you tried checking it in safe mode? Have you tried doing an operating system reinstallation?

David

Posted on May 11, 2013

Testimonial: "Hi David, I have tried safe mode but not reinstalling the OS (WIN7ULT). When I first boot up, the screen backlight goes out before booting from the HDD. (I have also updated the BIOS and there is no settings in for the display). I am thinking of trying WIN8 so this should be a good way of ruling out the OS. If I remove the main HDD and use the second HDD and do a complete clean install of WIN8, this hopefully should prove the OS. Thanks "

  • Will Hampton May 12, 2013

    I have done a clean install of WIN8 and fault still persists.

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SOURCE: Laptop LCD won't display

Bad Video.... It is replaceable if you have dedicated Video,

Need to replace the motherboard if you have onboard (integrated)video..

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SOURCE: IBM T30 won't boot with LCD, but will boot OK with external eonitor

It means computer developed oxide on some contact, and this is causing a short that forces unit to shut down, laptop must be taken apart, dried properly, and eventually cleaned with circuit cleaning solution.
If problem stops when you turn to external display, then probably it is water or oxide in LCD ribbon cable connectors.

Posted on Aug 10, 2008

dcolvard
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SOURCE: No LCD Display, No External Monitor display

If you just replaced the systemboard, the video chip is not likely to be the problem. I would say to check the cable connections and the actual lcd, but you said that the external monitor is not working either and that is not dependent upon the cable or lcd. I would say that your systemboard is probably DOA, but just to be sure do you have another laptop to test it on?

Posted on Mar 21, 2009

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SOURCE: Laptop screen stays blank on powerup

You would be well advised to hit F8 and do a safe mode. Then check the disk. More details here: http://annoyances-resolved.blogspot.com/2009/09/laptop-wont-boot-and-shows-blank-screen.html

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SOURCE: Thinkpad X200 display problem. LCD backlight kept

try to check your video card..

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Why are all the lights on LCD screen on?


How to troubleshoot and fix video problems
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.


all-lights-lcd-screen-4ztirbadqll2ypvmakqp10pq-2-0.jpg
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.


http://www.laptoprepair101.com/wp-images/white-screen/1-laptop-white-screen.jpg
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.

http://www.laptoprepair101.com/wp-images/bad-laptop-video/washed-lcd-image-1.jpg
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.
REFERENCE: http://www.laptoprepair101.com/troubleshoot-fix-laptop-video-problems/
GOOD LUCK.

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Laptop display backlight turns off


check and change the display inverter. backlight problems are related to invereter.

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It might be the Cold Cathode Fluorescent Lamp.

I was thinking along the lines that the lid switch may be the problem, but this would turn the display off also.
(Where is the lid switch? Dunno. Sometimes a little post that sticks out of the Switch Cover, or is a hidden magnetic switch, and usually located near the Touchpad)

A note on the CCFL. It has Mercury vapor on it, just like it's 'bigger cousins'. (Home and business size Fluorescent tubes)

Average thickness is 2mm. That is a little larger than 1/16th of an Inch.
Average length is almost as long, as the LCD screen is in height.

Yes. Will break VERY easy, and contains poisonous Mercury.
You MAY opt to just replace the LCD screen.

http://www.laptoprepair101.com/laptop/2007/12/09/replace-laptop-backlight-ccfl-lamp/


The screen Inverter, and LCD screen are a MATCHED unit.
Usually when the screen Inverter proves to be bad, the Backlight is not far behind. (And vice-versa)

I usually do not post CCFL replacement, due to the Mercury poison hazard.

Note*
An LCD screen is composed of layers. These layers are aligned by the factory, and are kept in alignment by the metal Screen Frame, which surrounds them.

You MUST keep the layers aligned in the factory set position, when replacing a CCFL. (Or CCFL's if it uses two of them)
Breaking the CCFL bulb is not the only thing to watch out for.

http://www.ccflwarehouse.com/ccfllamps.html

Regards,
joecoolvette

http://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/43y6630_03.pdf

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Laptop LCD goes black after a few seconds


Hello,

Yes, The pink tint is an indication that the backlight is failing. Now the backlight is basically dead, the best way to get back going is to do an Ebay search for your model laptop and get a new screen. Most screens can be purchased for around $50.00 - $70.00 and they are very easy to swap. Email me if you need more info.

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The backlight is the light bult that illuminates the screen. Before it finally goes out completely it will turn your screen a pink color on startup (and then usually become brighter and the pink fades). It is also possible that the backlight, also called a Cold Cathode Flourescent Light, CCFL, died an immediate death. But usually they take a while and signal with the "PINKNESS" first. If you found that your computer is working just fine connected to an external monitor (and you moved the base of your laptop around while connected to the monitor to be sure and left the computer on for a long time) then you have verified that the screen is the problem. It is usually two things: (1) the inverter, a circuit board that increases the voltage to supply the LCD which eats around 700 volts (yeah baby); or (2) the backlight itself. The first problem is a relatively easy and inexpensive fix. You can find how to replace an inverter by downloading the Hardware Maintenance Manual for the T40, T41, etc., from IBM/Lenovo's site. Replacing the backlight itself, a bulb that is like a strand of speghetti and even more delicate, is a tougher job. I would suggest purchasing a replacement screen in that event rather than replacing the backlight yourself. (The HMM probably does not show you how to replace the backlight/CCFL as it is a potentially dangerous job.) That suggestion assumes you can find a cost-effective replacement screen and do not mind opening the TP and putting the new screen in. At least look at the HMM to see what is involved. Good luck.

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Hello,

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