The dead pixels of the monitor


The problem of dead pixels has been for years one of the most serious handicaps the LCD monitor .

The problem is due to the fact that the panel The LCD is manufactured in one piece , with the same techniques that use to produce microchips . Just an impurity or irregularity in the production and the resulting panel will be defective ; since then elements microelectronic , it is impossible to proceed to some kind of repair. If the manufacturer decides to use only the panels without defects , should probably throw in the middle of production , driving up a lot of the prices of products , which is why almost everyone chooses to sell Also the panels with ” small ” imperfections . For a year this part is in effect a standard, called ISO 13406-2 , which allows you to calculate the second objective parameters imperfections of a screen. The standard – a tome of nearly 150 pages – Identifies four different types of defective pixels ( always on, always dull, bright and colorful group of bad pixels ) .

Moreover , the standard subdivides monitors in four different classes: Class 1 devices are those no defective pixels , while from Class 2 to Class 4 is gradually assuming a higher number of dead pixels . The total number of defects considered allowable increases with the increase of the resolution of monitor , as the defect rate is expressed in pixels for faults million . Let’s see what this means in practice. Almost all the manufacturers claim that their monitors belong to the Class 2 ( in the absence of an explicit declaration , the product must be taken Class 1 ) .

The monitors we tested all have a resolution of 1,280 x 1,024 pixels , or 1.3 megapixels.

For this class the ISO standard provides for a maximum of 2 pixels that are always lit per million, a maximum of two pixels off per million and a maximum of five colored pixels per million , in addition, provides that there can be more than two pixels defective ( on or off ) in any area of 5 x 5 pixels and not more than three defective pixels always colored in an area of ​​5 x 5 .

Doing the math , we get that the maximum number of defects allowed in a monitor of Class 2 is 10 pixels in total. Above this value can be get the change of the product warranty . The dead pixels of the monitorUnfortunately, despite the ANSI standard has the force of law , many manufacturers still use parameters owners to decide on the replacement or less of the monitor.

The board , at this point, is to be put in writing , before purchase, the policy followed by the manufacturer, to avoid then having to turn to consumer associations to assert their rights . Even better, check yourself in the perfect shop operation of the sample to the desired monitor before purchasing it.

 

To try to repair the dead pixels, you can use this method:

Finding the Pixel burned off the monitor Finding a cloth, like that found in glasses Exert pressure is not too strong on the defective pixel with the cloth breast arrechiamo other damage At the time we exert pressure on the pixels turn on the monitor, and we release the pressure on the monitor
Repeat 5-6 once the transaction if the pixel does not go away.

 

Repairs stuck pixelsRepairs stuck pixels

 

One way to solve “by hand” the problem is trying to change quickly (a few tens of times per second) for a relatively long time (about an hour) to the pixel color indicted. To do this there are a couple of free software: JScreenFix, that being a Java applet is virtually platform. The result is not guaranteed, but it costs nothing to try  😛
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