Common faults and treatment methods of LED display

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 LED displays 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.

Method/Step

First. The whole screen is not bright, and 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 or not.

   3. The synchronization screen detects whether the green light of the communication between the sending card and the receiving card 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. The horizontal direction of several consecutive boards is not bright, 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 longitudinal direction of several consecutive boards is not bright, check whether the power supply of this column is normal.

Third. The whole unit board does not light up

  1. The horizontal direction of several consecutive boards is not bright, 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 longitudinal 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 pass pins of the upper and lower modules are connected.

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

Fifth, the unit board lacks color

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

Sixth, a unit board does not light up

 1. Whether +5V power or GND is supplied

 2. Is +5V and GND short circuit?

 3. Does the OE signal of 138 fifth leg have

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

 method:

 1. "Power +5V or GND

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

 3. Connect the open circuit and disconnect the short circuit

Seventh, the half or lower part of a unit board is not bright or displayed abnormally

  1. Whether there is OE signal on the 5th leg of 138;

  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 dual-row pins connected to the 245 are normal; (open circuit or short circuit)

method:

  1. Connect the OE signal

  2. Connect SCLK and RCK signals

  3. Connect the open circuit and disconnect the short circuit

  4. Connect the open circuit and disconnect the short circuit

Eighth. 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 line 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 missing and missing welding

  2. Connect the open circuit and disconnect the short circuit

  3. Fill up the unsoldered supplies and weld the missing ones