Not everyone likes using a TV or monitor with dead pixels. To avoid misunderstanding, the number of such points should be checked before purchasing the device.
Instructions
Step 1
Finding dead pixels in a moving image is extremely difficult. Ask the seller to connect a signal source to your TV or monitor that allows you to display continuous luminous fields of various colors and brightness on the screen. This can be, for example, a computer, digital camera or DVD player with a set of corresponding graphic files. A TV test chart will not work - you need solid solid fields.
Step 2
Check CRT TV or monitor only with a solid white background (or blue, if it has the function of displaying such a background when there is no signal). He shouldn't have dead pixels at all. If they are present, this is the result of burning-through of the phosphor due to the stoppage of the sweep. This can only mean one thing - the device failed, and then underwent repair. Either refuse to buy it, or ask the seller to give you a significant discount on it.
Step 3
On the screen of an LCD TV or monitor, broken dots may be permanently black, or permanently glow in one color or another. That is why, when checking such a device, sequentially display solid white fields of various colors on it. Some dead pixels will blend in with some fields and be clearly distinguished on others.
Step 4
Multiply the horizontal resolution of the matrix by the vertical, and you will find out the total number of dots on the monitor. Divide the number of dead pixels detected by the total number of million dots on the monitor.
Step 5
Look in the manual for the device for its class according to ISO13406-2. If not specified, it is usually assumed that the TV or monitor is Class II.
Step 6
Refuse to buy a TV or monitor, or demand a significant discount on it if you find more:
- zero dead pixels of any kind - for a class I device;
- two permanently white, or two permanently black, or five permanently colored broken pixels - for a class II device;
- five permanently white, or fifteen permanently black, or fifty permanently colored broken pixels - for a class III device;
- fifty permanently white, or one hundred and fifty permanently black, or five hundred permanently colored dead pixels - for a class IV device.
