Nowadays the LED Display Screen in market share more and more high, so the problems of also is increased, especially from the manufacturer for far users in the products have problems and not the fastest service to users will also bring serious loss. Here through the common problem of simple do introduction.
Unit board failure:
1. The whole board not bright
Check the power supply and power line is connected
Check test card is to identify interface, test card red light flashing is no recognition, inspection and testing whether the board with the power to card, or light board interface has signal and to short circuit can't identify interface.
74 HC245 virtual welding or testing short circuit, the corresponding to the 245 can (EN) signal input/output feet whether is empty welding or short circuit to the other lines.
Note: the main check the power supply and to make can (EN) signal.
2. Oblique scan in points, the regular interlaces not bright show scenes overlap
Check A, B, C, D signal input port to 245 between whether there is A break or A virtual welding, short circuit.
245 the corresponding detection A, B, C, D output terminal and 138 for open circuit or between virtual welding, short circuit.
Testing A, B, C, D between each signal whether short circuit or A signal and to short circuit.
Note: the main testing ABCD line signal.
3. The light has a line, or a few do not bright
Test between 138 to 4953 lines for open circuit or a virtual welding, short circuit.
4. In scanning, two line, or a few lines (it is power of 2, regular) and light
Testing A, B, C, D between each signal whether short circuit.
Testing whether the 4953 output with other output terminal short circuit.
5. The light is the single point or more (disorderly) not bright
Find the module of the corresponding control measuring whether feet with our short circuit.
Replace module or single lamp.
6. The light has a column or a few columns not bright
In the module control the column found on pins and the measured whether and drive IC (74 HC595 are needed, and TB62726 /,) the output connection.
7. A single point or a single highlighted, or an entire line highlighted, and not in control
Check whether the column with the power to short circuit.
Testing whether the bank with power positive short circuit.
Change the driver IC.
8. Display chaos, but output to the next board normal signal
245 the corresponding detection STB lock to save the output and the drive of IC latch whether the connection or signal is short circuit to the other lines.
9. Display chaos, the output is not normal
Detection clock CLK latch STB signal whether short circuit.
Detection of the clock CLK 245 whether have input output.
Testing the clock signal whether short circuit to the other lines.
Note: the main testing clock with lock to save signal.
10. Shows lack of color
Detection of the color of the 245 data is whether the input and output.
A test for the color of the data signals to other lines are short circuit.
A test for the color of the driver IC grade between even mouth whether there is open circuit or data short circuit, virtual welding.
Note: can use voltage method is easy to find problems, check the data of the mouth of the different voltage and normal whether, to determine the fault zone.
11. Output has a problem
Detection output interface to signal output of IC line is connected or short circuit.
Detection of outlets clock lock to save signal is normal or not.
Test last drive IC level between the output data even if the mouth with output interface data connection or whether the mouth of short circuit.
The output signal whether there is a short circuit or short circuit each other to the ground.
Check the row is good output line.
Through the above detection, basically will know the LED Display Screen unit board where's the problem here, which is to better solve the problem. Chipshow LED with high quality products and perfect service for your dedicated service, if you have any problems, please contact us.
