LED display maintenance and debugging

- May 15, 2019-

Remarks on treatment methods for adverse phenomena and causes


Scanning irregularity

1. Check whether there is A broken line or virtual welding and short circuit between signal input ports A,B,C and D and 245

2. Test whether there is open circuit or virtual welding and 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 there is A wrong connection or failure of A certain signal

4, when scanning, there is no normal scanning to check whether the clock (CLK) or latch (STB) signal and test card are connected incorrectly or not


When full light is on, one line or the same line does not light short circuit. Detect whether the line between 138 and 4953 is open circuit or virtual welding, short circuit


In line scanning, two or more lines (usually multiples of 2, regularly) simultaneously light a short circuit

1. Test whether there is a short circuit between signals of A.B.C.D

2. Test whether there is a short circuit between signals of A.B.C.D


When full light is on, one or more non-bright virtual soldering pins controlling the column are found on the module to test whether they are connected with the output end of drive IC(YZ5026/TB62726, etc.)


There are single point or single column brightness is too high, or the whole row brightness is too high, and uncontrolled


1. Check whether the column is short-circuited with the power supply.

2. Test whether the line is short-circuited with the positive pole of the power supply.

3. Replace its drive IC


There is a short circuit in the 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 at the output port is normal.

3. Test whether the output data port of the cascade connection between the last driver IC is connected with the data port of the output interface or whether it is short-circuited.

4. Whether the output signals are short-circuited to each other or to the ground.

5. Check whether the output wiring is good