How to repair outdoor advertising lights if part of them does not light up
一、The LED advertising screen displays a row of bright red
LED display outdoor module fault repair (taking P10-1R as an example)
1. The entire board does not light up: the board is not connected Power supply; the input cable is plugged in backwards; the input and output are reversed; the positive and negative poles of the power supply are connected reversely (reverse connection will burn out all the ICs on the board).
2. The board does not light up and the transmission is normal: The solution to the damage to the protection circuit is to short-circuit the 4th and 5th pins of 74HC138. 3. One of the three rows does not light up: 4953 is damaged (one of them is damaged).
4. Light up every other row: A signal problem, please check whether 74HC245 and 74HC138 are welded; you can use a multimeter to measure whether the voltage of pin 1 of 74HC138 is equal to about 2.5V. If so, replace 74HC138; carefully measure the gold pin strip ICA signal pathway.
5. The second row lights up every other row: There is a problem with the B signal. Please check whether there is a weak solder between 74HC245 and 74HC138; you can use a multimeter to measure whether the voltage of the second pin of 74HC138 is equal to about 2.5V. If so, replace the 74HC138; carefully measure the gold pin. Pathway conditions with ICA signals.
6. The upper half of the board is normally fully lit or the lower half of the board is not lit: If this is the case with the T08A interface, you should check whether the DR data signal of the lower 8 lines is connected. If it is normal, replace the 74HC245 first. If not, try again. Replace the first 74HC595.
7. The STB and CLK signals of the upper and lower boards on this board are common, and the data are separated (if it is a T12 interface data, it is also one). If the T08A board is inspected as upper and lower half boards, they must be inspected separately.
8. If one lamp on the board does not light up: check whether there is a weak solder and replace the lamp.
9. There are 4 lamps that are standing vertically and do not light up: first, check whether the 74HC595 has a weak solder; second, replace the 74HC595; third, replace the lamp. 10. Among the four standing lamps, 3 are not lit and 1 is normal: replace the normal lamp.
11. If the board displays abnormally from the middle or other positions to the rear: check the data signal path; replace the last 74HC595 that normally displays and controls the light; if it is not ruled out, replace the first one that displays abnormal light control. 74HC595. Each 74HC595 controls 8 points wide * 4 points high lamps. 74HC595 is connected in series with DR data signals, that is, the DR signal goes from pin 14 to pin 9 of the 74HC595 to pin 14 of the next 74HC595 to the last 74HC595. For example, the DR data of this board goes from the gold pin to the 74HC345 After zooming in, go to UR1, UR2, UR3, all the way to UR8 and then to the output gold pin.
12. Sometimes during the process of debugging the entire screen, the display from the front module to the rear module is abnormal. The general fault is that the cable is not plugged in properly or is damaged; you can also use a slightly longer cable to straighten the lower part. Plug the cable of the module you are checking into the abnormal module above and see what the display is. You can also connect the output of the normal module in front of the abnormal module to the next row of modules to see what the display is like to determine which module it is. There is a problem with the group. Note: The maintenance principles for other models are the same
1. The entire board does not light up: the board is not connected Power supply; the input cable is plugged in backwards; the input and output are reversed; the positive and negative poles of the power supply are connected reversely (reverse connection will burn out all the ICs on the board).
2. The board does not light up and the transmission is normal: The solution to the damage to the protection circuit is to short-circuit the 4th and 5th pins of 74HC138. 3. One of the three rows does not light up: 4953 is damaged (one of them is damaged).
4. Light up every other row: A signal problem, please check whether 74HC245 and 74HC138 are welded; you can use a multimeter to measure whether the voltage of pin 1 of 74HC138 is equal to about 2.5V. If so, replace 74HC138; carefully measure the gold pin strip ICA signal pathway.
5. The second row lights up every other row: There is a problem with the B signal. Please check whether there is a weak solder between 74HC245 and 74HC138; you can use a multimeter to measure whether the voltage of the second pin of 74HC138 is equal to about 2.5V. If so, replace the 74HC138; carefully measure the gold pin. Pathway conditions with ICA signals.
6. The upper half of the board is normally fully lit or the lower half of the board is not lit: If this is the case with the T08A interface, you should check whether the DR data signal of the lower 8 lines is connected. If it is normal, replace the 74HC245 first. If not, try again. Replace the first 74HC595.
7. The STB and CLK signals of the upper and lower boards on this board are common, and the data are separated (if it is a T12 interface data, it is also one). If the T08A board is inspected as upper and lower half boards, they must be inspected separately.
8. If one lamp on the board does not light up: check whether there is a weak solder and replace the lamp.
9. There are 4 lamps that are standing vertically and do not light up: first, check whether the 74HC595 has a weak solder; second, replace the 74HC595; third, replace the lamp. 10. Among the four standing lamps, 3 are not lit and 1 is normal: replace the normal lamp.
11. If the board displays abnormally from the middle or other positions to the rear: check the data signal path; replace the last 74HC595 that normally displays and controls the light; if it is not ruled out, replace the first one that displays abnormal light control. 74HC595. Each 74HC595 controls 8 points wide * 4 points high lamps. 74HC595 is connected in series with DR data signals, that is, the DR signal goes from pin 14 to pin 9 of the 74HC595 to pin 14 of the next 74HC595 to the last 74HC595. For example, the DR data of this board goes from the gold pin to the 74HC345 After zooming in, go to UR1, UR2, UR3, all the way to UR8 and then to the output gold pin.
12. Sometimes during the process of debugging the entire screen, the display from the front module to the rear module is abnormal. The general fault is that the cable is not plugged in properly or is damaged; you can also use a slightly longer cable to straighten the lower part. Plug the cable of the module you are checking into the abnormal module above and see what the display is. You can also connect the output of the normal module in front of the abnormal module to the next row of modules to see what the display is like to determine which module it is. There is a problem with the group. Note: The maintenance principles for other models are the same