Various problems often occur in the use of LED display screens. Today, we summarized the \"troubleshooting methods for the power supply board of outdoor LED display modules", which we share with you here.
A. The whole board does not light up
1. Check whether the power supply is connected to the signal line.
2. Check whether the test card can identify the interface. If the red light of the test card flashes, it will not be identified. Check whether the lamp board is grounded with the test card, or the lamp board interface has a short circuit between the signal and the ground, resulting in the failure to identify the interface.
3. Check whether 74hc245 has faulty soldering or short circuit, and whether the corresponding enable (EN) signal input / output pin on 245 has faulty soldering or short circuit to other lines. Note: mainly check the power supply and enable (EN) signal.
B. During oblique scanning, the regular interlaced lines do not light up, and the display screen overlaps
1. Check whether there is broken wire, faulty soldering or short circuit between a, B, C and D signal input ports and 245.
2. Check whether there is open circuit, faulty soldering or short circuit between output terminals a, B, C and d corresponding to 245 and 138.
3. Check whether there is a short circuit between signals a, B, C and D or whether a signal is short circuited to the ground. Note: it mainly detects ABCD line signal.
C. One or more lines do not light up when they are fully lit
1. Check whether the circuit between 138 and 4953 is open circuit, faulty soldering or short circuit.
D. During line scanning, two or more lines (generally a multiple of 2, regularly) are lit at the same time
1. Check whether there is a short circuit between signals a, B, C and D.
2. Check whether the 4953 output terminal is short circuited with other output terminals.
E. Single or multiple points (irregular) do not light up when fully lit
1. Find the control pin corresponding to the module and measure whether it is short circuited with this line.
2. Replace the module or single lamp.
F. One or more columns do not light up when they are fully lit
1. Find the pin that controls this column on the module and test whether it is connected to the output terminal of the drive IC (74hc595/tb62726).
G. Single point or single column highlight, or whole row highlight, and uncontrolled
1. Check whether the column is short circuited to power ground.
2. Check whether the line is short circuited to the positive pole of the power supply.
3. Replace its drive IC.
H. The display is disordered, but the signal output to the next board is normal
1. Detect whether the STB latch output terminal corresponding to 245 is connected with the latch terminal of the drive IC or whether the signal is short circuited to other lines.
I. Disordered display and abnormal output
1. Check whether the clock CLK latch STB signal is short circuited.
2. Check whether the clock CLK of 245 has input and output.
3. Check whether the clock signal is short circuited to other lines.
Note: it mainly detects clock and latch signal.
J. Display missing color
1. Detect whether the data terminal of the color of 245 has input and output.
2. Check whether the data signal of this color is short circuited to other lines.
3. Check whether there is open circuit, short circuit or faulty soldering at the cascade data port between the drive ICs of this color. Note: it is easy to find the problem by using the voltage detection method. Check whether the voltage of the data port is different from the normal one to determine the fault area.
K. Problem with output
1. Check whether the line from the output interface to the signal output IC is connected or short circuited.
2. Check whether the clock latch signal of the output port is normal.
3. Check whether the cascade output data port between the last drive IC is connected with the data port of the output interface or is short circuited.
4. Whether the output signals are short circuited to each other or to the ground.
5. Check whether the output cable is in good condition.
Thank you for watching. I hope it can solve your problems. Sostron is a commercial display solution provider that designs, manufactures, installs and operates LED screens worldwide. If you have any questions, you can consult us!