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Friday, February 6, 2009

Defective pixels on a liquid crystal display


Testing a new LCD monitor before purchasing, or an already purchased monitor during the warranty period (you may get a replacement according to the manufacturer's dead pixel policy) with the following freebies:
1)DefectPX
DefectPX allows you to easily check for dead or defective pixels on LCD monitors. DefectPX fills the entire screen with one of the colors that make up a pixel, allowing you to inspect the screen for pixels that do not match the selected color. DefectPX is easy to use and it has a very intuitive interface.

DefectPX by PCFreed can be run directly without having to install it on your computer: just download and run. An installer program is also available. Windows XP & Vista
Standalone
Installer

2) Dead pixel tester
Dead Pixel Tester, with display tests. TFT screens have thousands of pixels, on a 1024x768 monitor, there are three cells for each pixel - one each for red, green, and blue - which amounts to nearly 2.4 million cells (1024x768x 3 = 2,359,296). There's only a slim chance that all of these will be perfect; more likely, some will be stuck on (creating a "bright" defect) or dead (resulting in a "dark" defect). DPT was written to help me check my own screens (Couldn't find one that worked across multiple desktops so had to write my own!) by cycling through the three primary colours used (red,green,blue) and all on (white) and all off (black).

Simply select a colour then closely inspect your monitor in each of the primary colours checking for pixels that are not operating as expected. Stuck pixels (always on) are easier to notice than pixels that are not on due to their size (normally under .5mm). This application is freely distributable for non commercial gain, for any other usage please contact publisher.

All Windows
Download


3) Updated 9 Feb 2009.

Provide a photo capture and supplier would be glad to verify if it is within the industry standard.

Monitor Self-Testing
a. Shut down your computer and leave the power cord to the monitor connected and power on only the power socket.
b. Unplug the VGA cable (blue head connector with 2 screws) that is connected to the monitor itself.
c. By doing so, it will trigger the monitor self test.
d. A small box with horizontal line (red, blue, green) will appear on the screen.
e. Let the small box to move around and please observe any symptoms while it is moving.

Test in BIOS mode
a. Shut down your computer.
b. Power on your computer, upon seeing the log, tap on the button to enter the BIOS setup menu.
(Note: If after restarting, it goes into Windows, please turn off your computer and repeat step b)



Dell LCD Display Pixel Policy

During the LCD Monitor manufacturing process, it is not uncommon for one or more pixels to become fixed in an unchanging state. The visible result is a fixed pixel that appears as an extremely tiny dark or bright discolored dot. When the pixel remains permanently lit, it is known as a “bright dot.” When the pixel remains black, it is known as a “dark dot.”

In almost every case, these fixed pixels are hard to see and do not detract from display quality or usability. A display with 1 to 5 bright or dark dots is considered normal and within industry standards. Dell LCD Replacement Policy

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A defective (dead or stuck) pixel on a liquid crystal display (LCD) is a pixel that does not illuminate properly or does not display the correct color output. It usually looks like an annoying black, white or colored spot on your screen. ISO 13406-2 distinguishes between three different types of defective pixels:

1. Hot pixels (always on)
2. Dead pixels (always off)
3. Stuck pixels (one or two sub-pixels are always on or always off)


A permanently lit white pixel is called a glowing pixel. Hot pixels are usually best seen against a dark background. A dead pixel is a defective pixel that remains unlit. Dead pixels are usually best seen against a white background. A stuck pixel will usually be most visible against a black background, where it will appear red, green, blue, cyan, magenta, or yellow, although stuck red, green, or blue pixels are most common. A stuck pixel results from a manufacturing defect, which leaves one or more of these sub-pixels permanently turned on or off. Stuck pixels are not guaranteed to be correctable, and can remain faulty for the life of the monitor, however might be fixed by flashing numerous colors with a very rapid intensity.

1) Fix Stuck Pixel on LCD monitor with video flashing numerous colors with a very rapid intensity
Repair dead pixels on your LCD screen with this video
Download Video here.
This video here has rapidly changing colors play it and drag the video to the stuck pixel to fix stuck pixel.

2) Fix Stuck Pixel on LCD monitor with Dead Pixel Tester.


Defective pixels in LCD screens can sometimes be improved by mechanically manipulating the area around a defective pixel by pressing or tapping. This can help to evenly distribute the oil inside the screen, but it can also damage it.
(For more information read this Wikipedia article.)

Related external post: How to Fix a Stuck Pixel on an LCD Monitor

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1 comments:

RearVuMirr said...

Cool post ~ if I ever decide to splurge on one I'll be back!

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