T400 Screen - No backlight

Hi everyone
On my lenovo t400, the screen is black but with enough light you can see the display.
There's no backlight. At one point, dimming the screen brightness allowed me too see but the
Screen started turning red and the backlight died but with light I can still see.
I use an external monitor which works.
Do I have the replace the entire screen or just the LCD inverter board to this
Anyone?

If I buy an LCD inverter board nd swap it and it doesnt work, its most likely the motherboard ?
richk wrote:
It has been my experience that the cable is the least likely thing to fail, so I would try that last. If you have a CCFL backlight, I would try the inverter because it is cheap and fairly easy to swap. If it is an LED backlight, my experience has been that the motherboard is most likely cause. You can check the parts list here if you are not sure:
http://support.lenovo.com/us/en/ibasepartslookup

Similar Messages

T400 screen problems...

Hi guys, I have a t400 that I purchased August of 2009, the LCD screen backlighting gradually messed up (i.e. half of it worked, or some sections would not have any backlighting while others would), so I changed it out. The panel was 42T0705, a WXGA LED backlit samsung screen. I bought the exact same FRU off of ebay, hooked it up, and booted my laptop up. However, I find that the screen's backlight is on completely, but there is nothing displayed on the screen; I know that the computer is fully booted, though, because I can hear the windows startup sound and all that. I tried hooking it up to an external monitor, but with no results. Suggestions?
Btw, I have the integrated graphics option, and a P8xxx series processor.

Does putting in the original one work?
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T400s Screen Color Issue

Anyone have a color-mismatch issue? T400s screen is at factory default but the colors are definitely different from desktop screen rendering. Have tested photographs on different screens and the T400s is much cooler (less red). Also, hypertext links are a lighter blue on the T400s vs. more blue/purple on the desktop monitor. This has been tested on a Samsung desktop monitor, a MacPro laptop, a Dell desktop monitor. All are the same except for the T400s.
Any comments are appreciated!

Hi sdreyer,
Welcome to the Lenovo forum!
Color perception is a fascinating subject, you can find more about it and monitor calibration at this post and the links therein.
Best regards,
Frank
Results of Your Ideal Business-Class Laptop survey, concluded 2009-07-29.
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Thinkpad T400 Screen broken

Basically, I set my laptop down on my books too hard, and the LCD cracked(Not horribly, but I want it replaced).
After a while of searching with lenovo's system, this is what I found:
http://gyazo.com/b8b094e346dd7263d26c5986d48ea8b5.png
So I assume I need an LCD with Manufacturer's P/N of 42T0495? Does it have to have that part number, or is it fine to find any other PANEL LGD 14.1" WXGA from a thinkpad, or do I have to have a LCD with the FRU number that is the same as it says on the page?
Where would you recommend me buy the LCD?
Any help would be appreciated.
thanks
Solved!
Go to Solution.

Will this screen work?
http://www.ebay.com/itm/380653720307?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
According to your posts, I think it does. But I just want to confirm.
Also, from the photos on eBay, the some LCDs for the screen seem to have different cables on the LCD.
When I opened up my laptop, I took a look at the back of the LCD, there was no cable runnning down from it.
T400 screen with no cable running from it:
http://www.ebay.com/itm/Lenovo-Thinkpad-R400-T400-14-1-LCD-WXGA-Screen-B141EW05-V-3-42T0699-grade-b-...
Screen with Cable running down the back:
http://www.ebay.com/itm/ThinkPad-T400-14-1-LCD-Screen-Panel-42T0580-42T0581-Samsung-LTN141W1-L05-WXG...
Or maybe I'm just being really stupid, cause I unplugged a cable when I removed the LCD. Is that what it is?
Take apart video I used:
http://www.youtube.com/watch?v=i2R4oUUM5nc (skip to 3:20 for when he takes off the LCD)
Thanks so much for your help.

T400 screen brightness frequently resets

My T400 screen brightness resets to its lowest value intermittently. Sometimes it takes only 30 seconds, sometimes it's several minutes. If I press a key, it goes back to the bright setting. I didn't intentionally change any power or screen settings, and none of the settings I can find (Windows or ThinkVantage power settings) indicate that this should happen.
Any idea what's going on?
Thanks.
Message Edited by allanbracker on 08-11-2009 10:44 AM

@Jeffw3030,
try this.
http://forums.lenovo.com/t5/T400-T500-and-newer-T-series/T410-Screen-flickering-randomly-screen-cont...
//JameZ
Check out the Community Knowledge Base for hints and tips.
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T400 Screen flickers, when I connect power adapater in my home

T400 Screen flickers, when I connect power adapater in my home. When I connect the same power adapter in my office. It works fine. Can any one please suggest me, what's the issue with the T400 laptop. If it's a issue with my power supply in my home , how all other computers are working.

Hi Snowfall,
Have you resolved your flickering issue? It looks like I have the same on my Ideapad Y550P. Screen flickers occasionally when I work connected to the power adapter at home. And what is more concerning is that the brightness control also stops functioning sometimes.
In your case how has the situation evolved? Has your laptop been repaired or you just live with it as is or has the issue deteriorated into something worse? Just want to get some arguments in my discussions with the SL2 support who cannot reproduce the problem in their office...
Any extra informaton is much appreciated.
Regards, Alexey

T400 Screen Issue - Half Dark

I have been having issues with my screen /backlight in the last month. I actually took a video of the problem hoping it would give you a better idea of what's going on.
I have a WXGA LED screen 1280x800 w/ camera and keyboard light. T400 purchased Dec 2009.
Symptoms:
- Right side of the screen is visible but a lot darker than the left
- Adjusting brightness does not work on either side when it is like that
- Sometimes screen will flicker ever so lightly
- Sometimes screen will go completely dark, but text is barely visible if you look at point blank range (backlight issue?)
- Closing the screen for sleep mode and then awakening will fix the problem, sometimes for extended periods (hours), sometimes for seconds
- When the screen is working properly, changing brightness works; however adjusting to darkest setting will only yield a darker right side, and no change on the left
- Sensitive to movement; if the screen is working, moving the laptop around or adjusting the screen will cause right side to go dim or all to go dark.
Is the problem the led screen, backlight, connection, motherboard or something else?
Hopefully someone has seen this same problem and can help. Thanks!
Here is the video for reference.
http://www.youtube.com/watch?v=0O2cx9T4DI8

Yesterday I decided to open up the lcd assembly to examine and copy down the exact part # of my led sub card and lcd screen. I thought it had to be the sub card or lcd panel. But as i observed b4, the lcd would work fine for hours as long as the laptop was on a stable flat surface, which led me to believe the lcd should be ok.
Anyways, after removing the front and back bezels, I detached and reattached the led sub card. Then I visually inspected the lcd panel. Everything looked fine.
I turned it on and lo and behold, the screen has been working perfectly for the last 24 hrs. No dimness, no blackout.
My conclusion is that perhaps one or both connections on the led sub card were not seated properly. Anyways, I will continue to observe and hopefully, everything is fine now, knock on wood.

T400 screen issues.

Hello All,
I picked up a T400 way back in the summer, but I had just recently noticed that there're a patch of bright pixels near the bottom left of my screen. I have the WXGA+ LED backlight screen. The pixels aren't dead as they still still show colour and whatnot, they're just...really bright. The difference in brightness is most noticable on white/light colour backgrounds.
I was wondering if anyone else has seen this problem before, and if it'll be something covered under warrenty.
As well. has anyone else noticed that the keyboard presses against the LCD when closed? after a while i noticed keyboard imprints on my screen. Luckily I've been able to clean off the prints with screen cleaner and a microfibre cloth. I'm just slightly worried about issues further down the road.
Anyway, Thanks in advance guys, I'll try to get pictures of the bright patches soon.
Jason

can you post a link of the pictures that shows this defect, if it is not user induced it maybe covered under warranty, but you would need to call Lenovo service in regard to the actual condition to the warranty coverage.
Regards,
Jin Li
May this year, be the year of 'DO'!
I am a volunteer, and not a paid staff of Lenovo or Microsoft

T400 screens and Graphics

Hi All, looking at getting new t400, do all t400's have the LED backlight screen and is the ATI Mobility Radeon 256 DVMT one of the hybrid solutions, ie can switch between discrete and built in. The model I am looking at is 2765P5M (australian model)
Thanks for any advice.
Chris.

Hi chris72a,
The definitive place to look to answer such specification questions is the Lenovo Personal Systems Reference (download the ThinkPad Notebooks pdf).
Results of Your Ideal Business-Class Laptop survey, concluded 2009-07-29.
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T400 screen flashes then goes black

As the thread title says, my lenovo t400's screen recently started flashing. It wasn't that bad at first but it increased in frequency and started to be very annoying. I noticed changing from battery to cable would temporarily stop it, also turning down the brightness helped.
However the problem started getting worse and now when I am forced to have it on the lowest brightness settings. If I turn it up it starts flashing erratic and then the screen turns off. The system itself keeps working though and if I turn the laptop off or in sleep mode and then turn it on again the screen "works" again (still with flashing). Ofcourse if I left the brightness above its lowest level it will instantly go black again.
Also most likely related, half of the screen (left side) has taken on an "redish" collor.
What could be the problem and is it something I can fix myself?

naraga wrote:
On the back it says type: 6474-B84. I assume you mean that?
And yes if I were to shine on the screen with a flashlight I can see the content.
Correct, these are the original specs of the machine:
ThinkPad T400 (6474-B84):
P8600(2.4GHz), 2GB RAM, 160GB 7200rpm HD, 14.1in 1440x900 LCD, Intel 4500MHD, CDRW/DVDRW, Intel 802.11agn wireless, WWAN option, Bluetooth, Modem, 1Gb Ethernet, UltraNav, Secure Chip, 9c Li-Ion, WinXP Pro
I can think of three possibleculprits, LCD cable defective, inverter defective or LCD panel's backlight defective. The cable and the inverter will be cheaper to replace, the panel will be more pricey I guess, (I don't know the current LCD panel prices).
T400's came with standard CCFL and LED screens. You need to find out which one you have. You can try the part lookups page from Lenovo and follow the instructions here: http://support.lenovo.com/en_CH/product-and-parts/partsLookup.page?
(You need the machine type and your serial number, please don't post the serial number here in the forum)
P.S.: If you have a LED screen cluprits could be the cable or the panel, no inverters there AFAIK)
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A31/i1600/G40/R50p/R61i/S30/SL510/2*T22/4*T4x/11*T6x/6*T4x0x/6*T5x0/3*W5x0/W700/3*X2x/4*X3x/3*X4x/5*X6x/3*X6xT/10*X2xx/2*X200T/4*X30x/Z60m/3*Z61x
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T400 Screen Flicker: Cable, inverter, or LCD?

Within the past four months or so, my T400 (Win7 x64, switchable graphics, LED backlight) has developed an irritating though thusfar harmless flicker in the screen. There's no graphical distortion or blank screen, but the effect is like the brightness or sometimes the general contrast of the screen is getting tweaked back and forth between a few settings.
It's most definitely not OS related, as the issue occurs occasionally on bootup and in the BIOS screen, and I confirmed that it happened while I was running Ubuntu 12.04 from a USB stick. The problem occurrs whether I'm running on the integrated Intel graphics or on the discrete Radeon HD3470.
I was installing a memory upgrade the other day and I took the opportunity to try to check the connection of the LCD cable to the motherboard. Everything looked fine from that end, and I couldn't really find anything that would suggest a loose connection there.
The next step is to have a look at the connection inside the monitor, but I'm a little reluctant to crack it open--the way to Thinkpad innards is well documented and I have a more-or-less steady hand, but I also feel a little cursed from time to time in that electronics never quite fit back together the same way after I've opened them (how the heck do you even get the little screw covers off the screen? And what do you reattach them with?). I'd obviously like to check to see that the cable to the LCD is firmly seated, but if it were coming loose wouldn't I be having issues with the display itself cutting in and out or getting corrupted, rather than just this odd brightness adjustment? Are there any old hands out there that can immediately recognize this issue as symptoms of a failing LCD, or a bad inverter, or...?

gsl,
There isn't a T400 video but you can refer a bit on the T410 one.
http://frusonfone.com/fof/T410/index.html
Also you can check the HMM for T400.
Try reseating the cables on the LCD side and see if that helps. If no then I think next part to replace LCD Cable since its a cheaper part (hopefully that would eliminate the issue) worst come to worst then LCD panel replacement.
*Non Lenovo employee*
I have a Y2P (i5) ... Feel free to ping me if you want me to test some applications with your Y2P if you have the same model. I don't mind keep doing recovery on it if needed .... =)

T400 Screen turns Black/Gray and System Freezes.

My screen turns black or gray and the system freezes.
The only way to fix it is to restart the system by opening all forms of power supply (adaptor and the battery).
Sometimes it works fine for a day or two, sometimes only for a few hours.
I think the problem has something do with my graphics drivers or some other driver from Lenovo.
I have used Lenovo Thinkvantage Toolbox to check for hardware errors and it shows that everything is working fine.
I have updated all drivers but still the problem is there.
I still have warrenty period left.
I bought my system 2 years ago and have never had any problem untill this one.
My system specifications are given below.
Model: Lenovo Thinkpad T400 2764 CTO
BIOS version (Latest?): 3.18 (latest)
OS loaded (ex. Win 7 64bit): Microsoft Windows 7 Ultimate 64-bit
Lenovo default OS: Microsoft Windows Vista Basic 32-bit
Updates from TVSU completed? Yes.
Updates from Windows Update? Yes.
Power Manager Version: 3.25
RAM installed (brand and 1 x 4gb, 1 x 2gb, 2 x 2gb?) 2 x 2 GB
Model of discrete card: ATI Mobility Radeon 3400
Any error notification? No
3rd party application installed for the graphic card? No.
Any particular application which is running on the time this issue arises? No.
Running on battery? AC? Docked on station? Error occurs in any state.
Any solutions?
Anyone had similar problems?
Thanks.

My problem seems to be similar. Sometimes my screen also turns black unexpectedly and the notebook freezes completely! In some cases I see a bluescreen of death and in some very few cases it restarts automatically. If it does not restart automatically I have to hold down the power button for some seconds to turn the notebook completely off (so that the "power on led" left to the "battery led" is not illuminated any more). Thereafter it is possible to start the notebook again. So unlike user 400 I do not have to remove any connected power sources.
The issue seems to occur out of nowere and seems not to be related to the use of a specific software. My system is up to date with lenovo drivers and windows update, exept the BIOS, which I updated the system two times since the problem exists since more than half a year!!
I also give my system specifications below:
Model: Lenovo Thinkpad T400 2767 WC8
BIOS version: 3.16
OS: Windows 7 Professional x64
Updates from TVSU completed? Yes. (exept newest BIOS)
Updates from Windows Update? Yes.
Power Manager Version: 3.25
RAM installed 2 x 2 GB (bought and placed by loenovo reseller)
Model of discrete card and integrated card: ATI Mobility Radeon 3400 and intel mobility 4 chip
Any error notification? yes, entry for bsod or kernel-power-issue in the system protocol (but no specific error)
3rd party application installed for the graphic card? No.
Any particular application which is running on the time this issue arises? No.
I use my notebook with AC connected, with battery and most of the time in the advanced mini dock! Since a few days the error never happened when the notebook was docked! So I thought it is a power issue or has something to do with the graphics card.
But now I found out, that the issue might be related to the wlan card! This is because I never had a wireless lan connection when the notebook was docked, since I use a LAN cable. But a few days before I had to use the wlan while my notebook was docked and the error occured after some time. Furthermore, as far as I remember the issue never occured when the wireless lan was switched off and not docked, but I will check that again.
The issue also never occured when I booted windows in safe mode.
@400
Maybe you can check if it is the same for you with your wlan? Maybe together we can find out what the exact problem is. I want to find out what is the problem to get it fixed by lenovo. Until now they alwas said, that they had never experienced such an error.
Please keep on reporting.
Thanks for any help

What's wrong with my lenovo T400 screen?

My T400 ,1440x900, brought 2 years ago. The screen became shaking and resolution became horrible. On the top of the screen. there is a bright line. Since the warrant is already expired, how can I repair it?

Hello mate,
You can buy spare parts from Lenovo and change it yourself if you want.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information on it.
ThinkPad T510 4313-CTO Windows 8 x64 - Intel Core i7-620M - NVIDIA NVS 3100M - 8GB RAM - 240GB SSD- Intel Centrino Ultimate-N 6300 - Gobi 2000.
ThinkPad Helix 3697-CTO Windows 8.1 x64 - Intel Core i7-3667U - Intel HD Graphics 4000 - 8GB RAM- 256GB SSD - Intel Centrino Advanced-N 6205 - Ericsson C5621gw

Uneven screen whiteness/backlight

Has anyone else noticed an uneven backlight/screen whiteness? I just got my 16GB, and the screen is uneven.. Standing vertical, with the home button on the bottom, the right side of the screen is slightly yellow/warmer where the left side of the screen is very white and cooler.
I think I'm taking it in for an exchange, but I'm wondering how common this is. I know iPhones and iPod touches had this issue, but I wasn't expecting these to for some reason.

I see exactly the same issue. For me, when holding the iPad vertically, a vertical strip corresponding to the middle third of the screen is significantly darker than the rest. I don't notice this at all when the room is very bright or I am using the iPad outdoors, or in movies or games, but it drives me nuts when I am reading a book or other text on a white background.
I actually had this problem on my original iPad and had it exchanged, and still see this problem—a darker vertical strip. I'm not sure what to do now and I am starting to think that all iPads have the problem, although it could just be the two copies I have had.

Dark screen unless backlight turned on??

I previously owned an ipod mini and I didn't have to use the backlight feature unless I was in a dark room because the screen was still perfectly visible. With my new ipod nano 4th generation the screen is too dark to see at any time of day unless the backlight is on. Is there something wrong with my screen or is it supposed to be really dark to the point where you can't read it unless the backlight is on?
Thanks!!

Hello Pilsky,
I would be concerned too if the screen of my iPod nano remained dark. I recommend following the steps listed below.
These steps are for the iPod nano 6th generation. If you are using a different model of iPod nano, the only step that may be different is the step to reset the iPod. I have also included the article that includes to the steps to reset other iPod models, so be sure to reset your iPod according to that article:
Will not turn on or screen remains dark
Connect iPod to power for at least ten minutes to ensure that the battery has enough charge to allow iPod to turn on.
If iPod does not turn on after ten minutes, try resetting the device while it is still connected to power. Reset the iPod by holding down the Sleep/Wake button and the Volume Down button for at least eight seconds or until you see the Apple logo appear.
If the Apple logo appears on the display, connect iPod to a computer and verify that it appears in iTunes and can play music. If iPod appears in iTunes and can play music, no further troubleshooting is needed.
If the screen remains dark and will not turn on, then your iPod may need service.
iPod nano (6th generation): Hardware troubleshooting
http://support.apple.com/kb/ts3474
You can find the steps to reset alternate iPods here:
How to reset iPod
http://support.apple.com/kb/ht1320
Thank you for using Apple Support Communities.
Best,
Sheila M.

T400 Screen - No backlight

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