Nowadays, with the expansion of the market, LED display products are widely used, and the competition among LED display manufacturers has become increasingly fierce. Due to the continuation of the price war, the quality of the LED display has been severely affected. As a traditional electronic device, various problems are common. The following mainly introduces some common faults and solutions of LED large screens.

　　 One, the whole screen is not bright, the whole screen is black

　　 1. Check whether the power supply is energized.

　　2. Check whether the communication line of the synchronization screen is connected and whether it is connected incorrectly.

　　 3. The synchronization screen detects whether the green light of the sending card and the receiving card communication flickers.

　　4. If it is a synchronous screen, whether the computer monitor is protected, or the display area of the screen is black or pure blue.

　　 Second, the whole unit board does not light up

　　1. If several consecutive boards do not light up in the horizontal direction, check whether the cable connection between the normal unit board and the abnormal unit board is connected; or whether the chip 245 is normal.

　　2, the vertical direction of several consecutive boards is not bright, check whether the power supply of this column is normal.

　　 Second, the whole unit board does not light up

　　 1. If several consecutive boards do not light up in the horizontal direction, check whether the cable connection between the normal unit board and the abnormal unit board is connected; or whether the chip 245 is normal.

　　2, the vertical direction of several consecutive boards is not bright, check whether the power supply of this column is normal.

　　 Fourth, the unit board does not light up

　　 1. Check whether 595 is normal.

　　2. Check whether the corresponding through pins of the upper and lower modules are connected.

　　 3. Check whether there is a connection between the 595 output pin and the module pin.

　　 Five, the unit board lacks color

　　 1. Check whether the 245 R.G data is output.

　　 6. One unit board does not light up

　　1, whether +5V power or GND is supplied

　　2, +5V and GND are short circuit

　　3, 138 Does the OE signal of the fifth leg have

　　4, 245 connected OE signal is normal (open circuit or short circuit);

　　Method: 1. "Power on +5V or GND

　　2, "Disconnect the short-circuited one" and supply the OE signal

　　3. Connect the open circuit and disconnect the short circuit

　　 Seven, one half or the bottom half of the board is not bright or the display is abnormal

　　1, whether the 5th leg OE signal of 138 is available;

　　2, whether the signals of the 11th and 12th legs of 74HC595 are normal; (SCLK, RCK)

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

　　4. Whether the SCLK and RCK signals of the double-row pins connected to 245 are normal; (open circuit or short circuit)

　　Method: 1. Connect the OE signal

　　2, connect the SCLK and RCK signals

　　 3. Connect the open circuit and disconnect the short circuit

　　 4. Connect the open circuit and disconnect the short circuit

　　 8. A row on a unit board or the row of a corresponding module is not bright or displayed abnormally

　　1. Check whether the line signal pins of the corresponding module are soldered or missed;

　　2, check whether the corresponding pin of the row signal and 4953 is disconnected or short-circuited with other signals

　　3, check whether the up and down resistance of the line signal is not soldered or missed

　　4, whether the line signal output by 74HC138 and the corresponding 4953 is disconnected or short-circuited with other signals

　　Method: 1. Solder the false or missing solder

　　2, connect the open circuit and disconnect the short circuit

　　3. Fill up the unsoldered ones and solder the missing ones