Question about IBM ThinkPad T21 Notebook

1 Answer

LCD and inverter replaced, still dark

I replaced the LCD and inverter on my T21, but still no backlight. I'm running dual right now...the external monitor runs fine and the lcd is mirroring the image.....

Posted by on

  • sayre108 Mar 25, 2008

    the suspend light stays on

×

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Governor:

    An expert whose answer gotĀ voted for 20 times.

    Scholar:

    An expert who has written 20 answers of more than 400 characters.

  • Expert
  • 105 Answers

The most common fault here is certainly the screen cable - it is available cheaply on ebay - I'm in the UK so here is a local example in this link:

T23 Cable

the other slim possibility is failure of the backlight switch which detects when the screen lid is closed.

Please rate this assistance as we depend on your feedback - hopefully this should be fixya - thanks,

Posted on Mar 24, 2008

  • dave donert Apr 02, 2008

    Please rate this assistance - technical help was given free but we rely on your feedback!

×

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

T42p display lights for a couple of minutes through startup then goes dark


But fan still runs, and it sounds like the harddrive is spinning?

Diagnose.

Do you have a VGA monitor available?
You can use a CRT type, (Looks like a small TV), or a flat LCD screen monitor if it has a VGA cable.

http://en.wikipedia.org/wiki/VGA_connector

1) Laptop OFF, monitor OFF, connect the VGA monitor cable to the left side of the ThinkPad T42. (DisplayPort)

2) Turn the monitor on. If a CRT type allow it to warm up.
Turn the laptop on.

By factory default, the display should show on the external VGA monitor.
If not;

There are at least three display options available;
1) Internal monitor of laptop ONLY
2) Internal monitor of laptop AND external VGA monitor
3) External VGA monitor ONLY.

Press, and hold down on the Fn key, and at the same time tap once on the F7 key. The F7 key is the Display Toggle-Over key.

3) Good display on external monitor?
Problem is the video cable, or inside the Display Assembly.

Since the display goes dark after a couple of minutes, I can tell you the problem is the screen Inverter, or Backlight.
(Inside the Display Assembly)

90 PERCENT OF THE TIME the fault is a bad screen Inverter.

Primer:
An LCD screen cannot produce light. It needs an additional light source.
A Backlight is the additional light source.

A Backlight can be a CCFL, or a series of LED's.
(Light Emitting Diode)

The Lenovo ThinkPad T42 series of Notebook PC's, uses a single CCFL for a Backlight,

http://www.screentekinc.com/IBM__ThinkPad__T42-series-laptops-lcd-screens.shtml

A CCFL is a Cold Cathode Fluorescent Lamp. (Bulb)
Similar to Fluorescent lighting used in homes, and businesses, but on a MUCH smaller scale.

[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 ]

A screen Inverter converts the power from the laptop, for the LCD screen, and Backlight.

(Older versions of backlighting that used a series of LED's, used a screen Inverter. Newer versions do not. For these replace the LCD screen)

A screen Inverter and an LCD screen are a MATCHED unit. Make sure you get the correct screen Inverter, or LCD screen, when buying.

Primer over.

One example of a screen Inverter for the T42's,

http://battery-adapter.com/product_info.php/products_id/3381/vThinkpad+T42

Pictorial guide for replacing a screen Inverter, in a ThinkPad T42 series of Notebook PC,

http://www.insidemylaptop.com/replace-screen-inverter-in-ibm-thinkpad-t40-t40p-t41-t41p-t42-t42p-laptops/

http://www.laptoprepair101.com/laptop/2007/01/31/replace-screen-inverter-fix-backlight/

Lenovo Support link to the Hardware Maintenance Manual, for the ThinkPad T42 series of Notebook PC's,
(HMM. It is a Service Manual),

http://support.lenovo.com/en_US/guides-and-manuals/default.page?

Click on the bold black subheading -
Hardware maintenance manuals
Then click on the blue -> [+] Click for files

It is a PDF file.
It may take up to 30 seconds before the first page comes up.

For additional questions please post in a Comment.
Regards,
joecoolvette

Jul 29, 2012 | Lenovo ThinkPad T42 Notebook

1 Answer

My brightness control does not work just turned on and can not hardly see anything it is up and running what now


Have you tested it with an external monitor?

I would say you either have a damaged inverter board or screen baclight lamp. Usually the inverter board fails in one of the following ways:

1. When you turn on the laptop, the screen lights up for a short period of time and then goes dark. You still can see an image but it is very dark, almost invisible and definitely not usable. When you restart the laptop, the screen lights up and then goes dark again. The laptop works fine with an external monitor.
2. Your laptop turns on but the screen remains dark all the time. You still can see a very dim image outline. The laptop works fine with an external monitor.
3. The laptop screen works fine for hours or even days, but sometimes it goes very dark as it mentioned above. When you restart the laptop, the screen works fine again.

Inverter failure symptoms are very similar to backlight lamp failure symptoms and in most cases you cannot tell which one is causing the problem until you replace either the inverter board or the backlight lamp. From my personal experience, inverter boards fail more often than backlight lamps. If you have to guess, replace the inverter first.

Mar 24, 2010 | Dell Inspiron 1545 Notebook

1 Answer

ThinkPad T21 dark monitor. What part to change?


seems like a bad inverter that needs changing

Jul 03, 2009 | PC Laptops

1 Answer

Dv4000 hp pavilion dark screen


Have you replace the lcd inverter? if it works on external monitor, given the screen is new, then it leaves the inverter. Usually in the case of dark screen, it should be the first thing to check/replace.

Apr 07, 2009 | HP Pavilion dv4000 Notebook

1 Answer

Dark unreadable screen


If you see a dim image or flicking image on the LCD screen it means you have a backlight problem.
Connect an external monitor to the laptop and power it up, if you see a clear image on an external monitor, this means your video card is OK.

Dim image and/or dark display on the laptop's LCD screen indicates a faulty LCD backlight and it could be the inverter that supplies high voltage to the CCFL lamp or it is the CCLF lamp is nearly burnt out or burnt out, most likely this is the case.
The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
Check out www.lcdparts.net for parts, repair service and DIY info.

Mar 13, 2009 | HP Pavilion dv6000z Notebook

1 Answer

Dark screen on me laptop


the LCD backlight has failed, you will need to replace the LCD assy (about $200)

Jan 18, 2009 | Dell Inspiron 5150 Notebook

1 Answer

Dark Screen Inspiron 9100


If you replaced the inverter board and its still dark you need and new backlight itself http://cgi.ebay.com/LCD-Backlight-Lamp-for-Dell-Inspiron-9100-15-4-WXGA_W0QQitemZ150217509448QQcmdZViewItem

Dec 10, 2008 | Dell Inspiron 9100 Notebook

1 Answer

Back light on ibm t21


This is an known problem I think you must replace the backlight:
look for example ebay partnr: 260327530145
only for example if this is your problem.

PRODUCTS ITEMS

LCD CCFL BACKLIGHT LAMP IBM THINKPAD T20 T21 14.1" SCREEN

LAPTOP & MONITOR LCD SCREEN PROBLEMS

SOME COMMON SYMPTOMS FOR BACKLIGHT LAMP REPLACEMENT

- Flickering, red or pinkish hue to display and even total darkness. These symptoms are a result of a failed or ageing backlight or a failed, damaged. This is caused by the defective backlight lamp and all you need to do is replace the backlight.

DESCRIPTION

Our high brightness LCD cold cathode lamp (CCFL) with long life, it is more than 50000 hours, with Japanese new cathode, phosphor, glass, and other materials, they are perfect for all LCD backlight application and other purpose, such as instrumentation, medical devices, and all type devices.

COMPATIBLE MODELS
Suit for

Any 14.1” LCD Screen (2.0mm in diameter and 290mm Length) and (2.0mm in diameter and 292mm Length)

CUSTOMER SERVICE / CONTACT US

Email: mkproco@gmail.com (12 Hours Response Time)

Oct 14, 2008 | IBM ThinkPad T21 Notebook

5 Answers

IBM ThinkPad T21 LCD display very dark


The problem can be at the flexible cable that connecting mainboard to LCD panel. There are two line that connecting to backlight lamp. The position of the broken cable is in bottom-center of LCD. One or more line/track broken can resulting : LCD blank or LCD display very dark. The solution is : jumper the broken line with jumper cable & soldering.Or you must replace the flexible cable.
Goodluck..

Dec 29, 2007 | IBM ThinkPad T21 Notebook

Not finding what you are looking for?
IBM ThinkPad T21 Notebook Logo

227 people viewed this question

Ask a Question

Usually answered in minutes!

Top IBM PC Laptops Experts

John mullen

Level 2 Expert

245 Answers

Vicegrip
Vicegrip

Level 1 Expert

29 Answers

gbob59

Level 3 Expert

2963 Answers

Are you an IBM PC Laptop Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...