F:What is virtual pixel, real pixel?
Q:
    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.

F：LED Display Maintenance Procedures
Q：
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.

F：LED Display Screen FAQ and solution？
Q：
1. Whole screen does not work (black screen)
 (1)  Check power supply
 (2)  Check signal connection (cat5,DVI cable)  (synchronous screen)
 (3)  If synchronous screen, check the green led of sending card and receiving card whether it is twinkling or not.
 (4)  Check the monitor of PC whether it is protected as black,or screen display area is black or pure blue. (synchronous screen)
 
2.Whole LED module does not work(black module)
 (1)  Successive modules in horizontal do not work, please check the ribbon cable between the  normal unit module and unnormal unit module whether it is connectted or not, or replace the first module from right side when facing the screen.
(2)  Successive moudels in vertical do not work,please check the power supply of all the modules.
 
3.One row lamps of module does not work.
 (1)  Check this row whether connecting to output pin of 4953.
(2)  Check 138 encoder.
 (3)  Check 4953.
 (4)  Check Vcc and GND of 4953.
 (5)  Check output of 74HC138 and 4953's controlling pin whether connectted or not.
 
4.Unit module doesn't work.
 (1)  Check 595 normal or not.
 (2)  Checking the up and down moudle corresponded common pin connect or not.
 (3)  Check 595 output pin to moudle pin connect or not.

5.One color lacked in half or whole LED panel.
 (1)  Check 245 R, G, B data output.
 (2)  Check normal 595 output pin and unmormal 595 input pin whether it is connectted well or not.

F：LED Module Malfunction and Solution？
Q：
1. Phenomenon: the whole display is flickering.
 Problem: signal poor connection. 
Solution: re-fix or re-connect signal cable.

2. Phenomenon: dusky LED
 Problem: The volage of switching power supply is unconsistent with LED voltage tag.
Solution: make sure the volage of swtiching power supply is consistent with LED. voltage tag.¡¡
 
3. Phenomenon: partial LEDs do not work.
 Problem:
 A. contact direction correct or not.
 B. power output wiring correct or not.
C. power wire anti-inserted or connectted inversely.
 
Solution:
 A. re-connect in a correct way.
 B. ensure the red wire connect the positive pole,black wire connect the negative pole.
 C. check partial the wrong connection , re-connect.

4. Phenomenon: all LEDs do not work
 Problem:
 A. no output of the switching power supply.
 B. wrong power connection.

solution:
A.connect the power switch input and test.
 B. check the positive and negative pole of the power supply whether it is right or not.