Fault causes and treatment:

The switch power supply provided with the +5V power supply on this board has no output, that is, the power supply fails, the screen can be closed first to measure whether there is a short circuit between the +5V power supply and 0V. (about 15 Ω normally, less than 12 Ω for short circuit, if the search short circuit, short circuit if Yin value is normal, that the power supply is damaged.

1. Visually test whether the module pin and integrated circuit corresponding to the fault on the board of the unit are virtual welding, short circuit or open circuit; If so, weld the pins.

2. Use a multimeter to measure whether the output voltage of HC595 is normal; If so, the HC595 output terminal is judged to be disconnected from the module input terminal; If not, judge HC595 is bad and replace it with HC595 integrated circuit of the same model (when replacing HC595 integrated circuit, pay attention not to disconnect the circuit lead).

1. Whether the signal of the fifth leg OE of 138 is available;

2. Whether the signal of the 11th and 12th legs of 74HC595 is normal; (SCLK, RCK)

3. Whether the connected OE signal is normal; (break or short-circuit)

4. Whether the SCLK and RCK signals connected with 245 by double-row insertion needle are normal; (break or short-circuit)

1. If there is a problem with the data line connecting this unit, re-plug the data line and pay attention to the direction or change a data line.

2. Replace the distribution board if there is a problem with the corresponding distribution board.

3. Unit board failure

1. Check whether the input row stitches are normal or short circuit with GND and +5V

2. Check whether the signal between input pin row and 245 is normal (short circuit or open circuit)

3, IC245 bad

Solutions:

1. Connect the broken circuit; 2. Disconnect the short circuit; 3

1. Whether +5V electricity or GND is supplied

2. Whether +5V and GND short-circuit

3. Do you have the OE signal for the fifth leg 138

4. Whether the OE signal connected to 245 is normal (open circuit or short circuit)

5. Bad data cable

Check whether the connecting pin of the upper and lower modules is connected.

Check whether the 595 output pin is connected to the module pin.

The signal acquisition line between the COM port and the data transmission card is not connected or the COM port of the computer itself is broken.

Solution: connect the data cable or replace the computer

General customers in the purchase of LED full-color display, the first thing to consider is the LED display specifications.

Let's see, LED full-color display size is determined by those factors:

1. Whether the environment of the display screen is outdoor, semi-outdoor or indoor, the corresponding waterproof requirements will be different if the environment is different.Outdoor waterproof requirements, generally in IP65 above.Depending on the environment you can determine its general range of choice is outdoor full-color display or semi-outdoor full-color display, or indoor full-color display!

2, the best observation position the distance from the installed screen, or visual distance, the distance is very important, it directly determines what you choose and buy the display model, general indoor full-color displays models are divided into P4, P6, P7.62, P8, P10, etc., outdoor full-color displays models are divided into P10, P12, P14, P16, P20 and so on, these are normal, also such as pixel screen, bar screen, screen for different types and different, such as only said routine, P at the back of the figure is the distance between lamp bead, the unit is mm,In general, our minimum visual distance is the size of the number after P.That P10 best spacing "10 meters, this method is only a rough estimate!

In addition, there is a more scientific and specific method, which is to use the density of light beads per square. For example, if the point density of P10 is 10000 points/square, the optimal distance is equal to 1400 divided by (the square root of point density).If P10 is 1400/10000 square root = 1400/100=14 meters, that is, the best observation distance of P10 display is 14 meters away!

The above two methods directly determine the specifications of the selected LED full-color display screen, that is, customers must pay attention to two points when purchasing: 1. The environment of the display screen.2. The distance between the optimal observation position and the position of the display screen.Only with this knowledge can you choose the LED full-color display that matches your environment and achieves the best effect.

1. The flatness

The flatness of the surface should be within 1mm to ensure that the display image does not distort, and local convex or concave will lead to dead Angle in the viewing Angle of the display screen.The flatness is mainly determined by the production process.

2. Brightness and viewing Angle

Indoor full color screen brightness should be above 800cd/m2, outdoor full color screen brightness should be above 1500cd/m2, to ensure the normal work of the display screen, otherwise it will be too low to see the image displayed.Brightness is mainly determined by the quality of LED core.

The size of the Angle directly determines the size of the screen audience, so bigger is better.The size of the viewing Angle is mainly determined by the encapsulation of the core.

White balance

White balance effect is one of the most important indicators of a display screen.In terms of chromatics, only when the proportion of the three primary colors of red, green and blue is 1:4:6:0.16, will pure white appear. If the actual proportion is a little bit different, the deviation of white balance will appear. In general, we should pay attention to whether the white is blue or yellowish green.The quality of the white balance is mainly determined by the control system of the display screen.

4. Reducibility of color

The color reducibility refers to the color reducibility of the display screen, that is, the color displayed on the display screen should be highly consistent with the color of the playback source, so as to ensure the authenticity of the image.

5. There is no Mosaic and dead spot phenomenon

Mosaic refers to the small four squares that are always bright or often black on the display screen, which is the phenomenon of module necrosis. The main reason is the poor quality of connectors used in the display screen.

Dead point refers to a single point on the display screen is often bright or often black, how much of the dead point is mainly determined by the quality of the tube core.

6. No color block

Color block refers to the obvious color difference between adjacent modules, and the color transition is based on the module. The color block phenomenon is mainly caused by poor control system, low gray level and low scanning frequency