The model of my laptop is TOSHIBA SATELLITE U400 MODEL NO. PSU40C-DW208C the problem is the backlight of the LCD is built in and no power on it, thats why i cannot totally see because its very dim color, but all the software and operating system is working what am i going to do? to buy a new LCD or ask somebody to fix the backlight

The plastic frame in front of the LCD screen is the Display Bezel.
The screen Inverter is mounted at the bottom of the Screen Frame.

[The LCD screen is an assembly of layers. There is a metal frame resembling a picture frame; which keeps these layers in the factory set alignment; the Screen Frame ]

Therefore easy access. Just remove Display Bezel.

To test a screen Inverter requires a sensitive multimeter; read fairly expensive,

http://www.fonerbooks.com/test.htm

Due to the above, ease of access to replace, and generally low cost; the screen Inverter is just replaced.

Then on to the Backlight if this doesn't repair the problem.

Which brings me to this;

Safety

https://www.laptopscreen.com/English/model/Toshiba/SATELLITE~A100/

The Toshiba Satellite A100-S8111TD Notebook PC, uses a single CCFL for a Backlight.

A CCFL is a Cold Cathode Fluorescent Lamp. (Bulb)
Similar to it's larger 'cousins' 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.
View the last 8 photos,

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

This means it is Highly breakable. Costs more in money to just replace the entire LCD screen, (Which has the Backlight built-in),
but cheaper when you compare to life, and limb.

Jus sayin'.

http://www.irisvista.com/tech/laptops/Toshiba-Satellite-A105/remove-replace-LCD-screen-1.htm

For additional questions please post in a Comment.

Regards,
joecoolvette

1) Toshiba Satellite P300-13j LCD screen example,

http://www.screentekinc.com/Toshiba_Satellite_P300D-13J--17-inch--1440x900-wxgaplus-laptop-lcd-screen.shtml

Thin Film Transistor (TFT) Active Matrix LCD screen, that is WXGA, and uses one CCFL for a Backlight.

2) http://www.lcds4less.com/ToshibaLaptop__Toshiba_Satellite_P300D-12L__laptop-screens.html

Thin Film Transistor (TFT) Active Matrix LCD screen, that is WXGA, and has 1 CCFL for a Backlight.

There is a pretty good chance. The screen Inverter and LCD screen are a matched unit. I would remove the screen Inverter from the P300-12L, and use it also.

Looks like this,

http://www.lcd-inverter-shop.com/Toshiba/Toshiba-Satellite-P300D.html

If I may ask;
1) Is there obvious damage to the LCD screen?

2) If there is not obvious damage to the LCD screen, have you used an external VGA monitor with the laptop?

To see if the problem is the graphics chipset, or the video cable, or inside the Display Assembly.

A) http://www.irisvista.com/tech/laptops/Toshiba-Satellite-P305/take-apart-notebook-1.htm

B) http://www.irisvista.com/tech/laptops/Toshiba-Satellite-P105-P100/remove-lcd-screen-inverter-1.htm


Post back in a Comment.
Regards,
joecoolvette

[Primer:
An LCD screen cannot produce light by itself,
(Click on the monitor icon,

http://solutions.3m.com/wps/portal/3M/en_US/NA_Optical/Systems/BehindTheScenes/Optics101/ )

It needs an additional light source. A Backlight is the additional light source.
A Backlight can be a CCFL, (Or two of them), or a series of LED's.

LED stands for Light Emitting Diode

CCFL stands for Cold Cathode Fluorescent Lamp.
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.

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

Observe the last 8 photos especially. This article shows you that the LCD screen is an assembly. It is composed of layers. Just like the 3M company's tutorial. Also shows general instructions for replacing a Backlight.

A screen Inverter is used to convert the power from the laptop, for the LCD screen, and Backlight.
It is a small circuit board, and is usually mounted towards the bottom of the LCD screen, and behind the Display Bezel.

A CCFL, (Or two of them), uses a screen Inverter.
LED backlighting however, may or may not use a screen Inverter.

Using LED's for backlighting is relatively new, when discussing backlighting technology.
Some of the first designs of LED backlighting does use a screen Inverter.
Newer designs do not seem to.

90 PERCENT OF THE TIME the problem can be attributed to a bad screen Inverter.

Mohammad,

Toshiba Satellite P100 screen Inverter replacement;

1) http://www.irisvista.com/tech/laptops/Toshiba-Satellite-P105-P100/remove-lcd-screen-inverter-1.htm

(You can click on any photo to enlarge it. At the top, and bottom of the page are the page numbers. They are in white; Page1 :: Page2 :: Find another model )

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

A Backlight (Present technology) is a CCFL, or a series of LED lights.
The Toshiba Satellite P100 series of Notebook PC's uses a CCFL.

Cold Cathode Fluorescent Lamp.
Similar to Fluorescent lighting used in homes, and businesses, but on a MUCH smaller scale.

Average size is approximately 2mm Thick, and the length is close to the height of the LCD screen. 2mm is a little larger than 1/16th of an inch.

This means the CCFL can be broken quite easily, as it is fragile. (You also DO NOT want to be cut by a Fluorescent lamp )

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

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

As previously stated in a Clarification, 90 PERCENT OF THE TIME the fault is the screen Inverter.

Regards,
joecoolvette

(I never request commendations, but thank you for offering.
We, the older techs here, feel that is begging.
3 years at FixYa so far.
Regards,
joecoolvette)

You should be able to find all Toshiba product downlads by going here. http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/home.jsp makre sure you have the whole model number which is the U400-???? I tried what you have here but there was no such model so I am thinking that this is not the entire number or the wrong one. Click on product support and it will open a window below it then click on laptop, select Satellite, and to assist in finding your model enter the model number in the model finding filter box. It should find your model and when you click on it, it will take you to all of the downloads for it.

It is probably a driver issue. First check the device manager, from the Control Panel. A red triangle with an X or a yellow triangle with an exclamation point indicate that the issue is with the driver.

http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/home.jsp?nav=Download will let you search for your model and download the XP sound driver.

The specific driver may be: http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/modelContent.jsp?ct=DL&os=&category=&moid=2043975&rpn=PSU41U&modelFilter=&selCategory=3&selFamily=1073768667# (using the Satellite Pro U400-S1001V above)

I hope this helps.

Cindy Wells

Hi, this user Guide should help you out. Satellite Pro U400 (GMAD00176010_SatProU400_08Mar14_Vista) User Guide -- Page: 196')" class="resultslink" href="http://askiris.toshiba.com/ToshibaSupportSite/search.do?cmd=displayKC&docType=kc&externalId=http--cdgenp01csdtoshibacom-content-support-manuaerguides-su2059900-GMAD00176010SatProU40008Mar14pdf&sliceId=pdfPage_196&dialogID=105204900&stateId=0 0 72239285" target="_self">Satellite Pro U400 (GMAD00176010_SatProU400_08Mar14_Vista) User Guide"Did this help?"

Bad Mother Bad

try this:
http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/modelContent.jsp?ct=DL&os=&category=&moid=2025185&rpn=PSU40U&modelFilter=U400-ST5404&selCategory=3&selFamily=1073768663

Yes you can downgrade it to windows xp. go to toshiba website www.toshiba.com and from there you can download the drivers for Windows XP. befor installing Windows XP please download the Network driver and save it on a CD or any other driver. Then install Windows XP. Install the network drivers, connect to the internet and install the other drivers required.

Thanks