What is virtual pixel, real pixel?
Real and virtual-pixel screen is the corresponding.
Simply, real pixel is each LED of three red-green-blue LED which constitute a screen display is only involved in the use of an imaging pixel, in order to obtain sufficient brightness
Virtual screen is to use software algorithms to control the LED of each color to participate in the final number of adjacent pixels of the image, making the lamp with less LED to achieve greater resolution, it can increase about four times resolution.
As we all know, the largest cost is Led chip for Led display, one of our target is that we can save the cost but do not less the brightness. The virtual technology is a development direction. The virtual technology is not  a simple tube to participate in imaging, it impact much for the brightness, gray. It requires the control system coordinate with the driver chips, to use the software algorithms and driver chips to combine response time, to save the Led cost but do not less the brightness.
 
LED Display Maintenance Procedures?
1. Control system
1) The entire screen is not bright or grid
Control of the host open whether or not 
Communication line is plugged or not
Sending card has been plugged or not
The data line of  multimedia card, capture card, sending card is connected well or not.
The switch position of JP1 or JP2 card is not ok¡±,open the host
The communication line plugged well
To re-insert the sending card
Connect the lines well of the multi-media card, collection card, sending card.
Adjusting the JP1, JP2 switch location
The protection of a computer monitor is good or not or display screen is black or blue. (Synchronous Screen)
2) Every time when start LED control system is not able to find COM port to send data between the signal,the acquisition card line is not connected or the computer COM itself is defective. Connected to the data line or replace the computer
3) The whole screen shake or double image, " to check the data line between the computer and screen.
Check the DVI cable between multimedia card and sending card
"Sending card is defective"please reinsert or replace the signal cable, to reinforce the port of DVI cable, or replace the sending card.
2. Drive part
1) Module can not light
Horizontal direction of few modules do not light, check the normal and abnormal module cable connection is well or not.
Or 245 chip is ok or not.
Vertical direction of few modules do not light,  check the power supply of this line is ok or not.
+5V or GND is supplied or not.
+5V or GND is short-circuit or not
2) The horizontal direction of modules or the corresponding module is not bright or abnormal display
To check the foot of corresponding module is pin-line signal leakage or welding, To check the signal on the line, the next is no welding or resistance welding leakage.
3) Two lines of one modules is bright at the same time(one of lines is normal, the other lines is bright all the time when display text.
Please check if corresponding two lines is short-circuit or not.
4) The first half or the second half , red or green do not light or do not display properly, it is lack of color for each module, please check 245 R.G B output is ok or not.
Check the normal output of 595 feet and abnormal 595 feet is passed or not
To see whether input feet is ok or  GND, +5 V is short-circuit or not.