【 Weak current College 】 led display unit board failure as well as handling 】

<br> <br> A complete Board is off. <br> 1. check the power supply and signal cable is connected. <br> 2. check whether the test card to identify the interface, the test card is not recognized by the .red light flashing, check the light plate with test card with power supply, or light Board interface has signal and to a short circuit causing unrecognized interface. (Intelligent test card) <br> 3, there is no deficiency detected 74HC245 welding short circuiting, .245 on corresponding enabling (EN) signal input output pin is soldered or short-circuit to other lines. <br> Note: check the power and enable (EN) signal. <br> B £ ® oblique in points, of the law when .scanning interface is not lit display overlapping <br> 1. check the A, B, C, D signal input to 245 is there between the broken line or soldered and short circuit. <br> 2. detection of 245 corresponding A, B, .C, D output and 138 between circuit breaker or soldered and short circuit. <br> 3. testing A, B, C, D the signal between the short circuit or short circuit of a signal and ground. <br> Note: the main .test ABCD line signals. <br> C £ ® full bright one line or several lines not lit <br> 1. detection of 138 to 4953 whether circuit breaker between lines or soldered and short circuit. <br> D £ ® in the line .scan, two lines or lines (usually multiples of 2, regularity of) at the same time light <br> 1. testing A, B, C, D the signal between the short circuit. <br> 2. detection of 4953 outputs are .short circuit with the other outputs. <br> When you full bright E. a single-point or multi-point (irregular) is not lit <br> 1. Locate the module corresponds to the control of foot measurement is our short circuit. .<br> 2. replace the module or a single lamp. <br> F.-when a column or columns is not lit <br> 1. in control column found on the module pin, if measured and driver (74HC595/TB62726, .,,) output-side connection. [fenye] <br> There is a single point G £ ® or single row highlighting, or highlighting the entire line, and not managed <br> 1. check whether the column and the power to the .circuit. <br> 2, testing whether the row and the power of positive electrode short circuit. <br> 3. replace the driver. <br> H. display confusion, but the output to a plate of good signal <br> 1 .. detection of 245 corresponds STB latch output and driver IC latch side is connected or signal is short circuit to another line. <br> I £ ® display confusion, the output is not working properly <br> 1. detection of clock CLK latch STB .signal is shorted. <br> 2. detection of 245 clock CLK for input and output. <br> 3. detection of the clock signal is shorted to other lines. <br> Note: the main test clock with latch signal. <br .> Lack the color displayed J. <br> 1. detection of the 245 color data end if input and output. <br> 2. detection of the color data signal is shorted to other lines. <br> 3, detect the color driver .between concatenated data port is open or short circuit, the virtual welding. <br> Note: you can use voltage detection method is easier to find the problem, test data of the normal voltage and to determine whether different fault zones. <br> K .. output problems <br> 1. detection output interface to the signal output IC circuit is connected or short circuit. <br> 2. detection output clock latch signal correctly. <br> 3. testing the last driver of the concatenated output data port .with the output interface data port connections or is shorted. <br> 4. output signals if there is mutual short circuit or short to ground. <br> 5. check the output of wire is good. <br> <br>.