Display failure maintenance analysis

**A. The entire board does not light up** 1. First, make sure that the power supply and signal cables are properly connected. A loose or disconnected cable can prevent the board from powering on. 2. Verify if the test card is recognizing the interface. If the test card’s red light is flashing but still not detecting the board, check if the light board is using the same power source as the test card. Also, ensure that the board’s interface is not shorted to ground, which could prevent it from being recognized. (This applies especially when using a smart test card.) 3. Inspect the 74HC245 chip for any short circuits. Check if its input and output pins are properly connected or if they are shorted to other lines. This can cause communication failure between the board and the test system. *Note: Focus mainly on checking the power supply and the enable (EN) signal, as these are common causes of failure.* **B. During point-sweep scanning, the regular interlaced display screen is not overlapped** 1. Check if the A, B, C, and D signal inputs to the 245 chip are disconnected or shorted. Any issues here can lead to incorrect signal transmission. 2. Ensure that the output terminals of the 245 chip connected to the 138 decoder are not open, shorted, or improperly soldered. 3. Test each of the A, B, C, and D signals for short circuits or grounding. A faulty signal line can disrupt the scanning process. *Note: The primary focus should be on testing the A, B, C, and D signal lines for continuity and integrity.* **C. One or several lines are off when all lights are on** 1. Check the connection between the 138 decoder and the 4953 driver. Look for any open circuits or short circuits in the wiring. A broken or damaged line can cause certain segments not to light up. **D. In line scanning, two or more lines (usually a multiple of two, regularity) light up at the same time** 1. Test whether the A, B, C, and D signals are shorted together. This can cause multiple lines to activate simultaneously. 2. Check if the output of the 4953 driver is shorted to other output terminals, leading to unintended lighting patterns. **E. When there is full light, there is a single point or multi-point (irregular)** 1. Check if the control pin of the affected module is shorted to another pin. This can cause erratic behavior in the display. 2. Replace the affected module or individual LED if the issue persists after checking the connections. **F. When there is one column or several columns that are not lit at the moment of bright** 1. Locate the pin on the module that controls the affected column and verify that it is properly connected to the output terminal of the driver IC (e.g., 74HC595 or TB62726). A poor connection may result in the column not lighting up. **G. There is single-point or single-column highlighting, or full-line highlighting, and it is not controlled** 1. Check if the column is shorted to the power supply ground. This can cause unexpected illumination. 2. Inspect the line for any short to the positive power supply. 3. If the issue continues, consider replacing the driver IC responsible for that section of the display. **H. The display is garbled, but the signal output to the next board is normal** 1. Check if the STB latch output of the 245 chip is properly connected to the latch of the driver IC. A misconnection or short circuit can cause display distortion. **I. The display is confusing, the output is abnormal** 1. Check if the clock (CLK) and latch (STB) signals are shorted. These signals are critical for proper timing and data latching. 2. Confirm that the CLK signal has both input and output functionality. A broken clock signal can cause chaotic display behavior. 3. Inspect the clock signal for any short circuits to other lines. *Note: The main focus should be on verifying the clock and latch signals for integrity and proper operation.* **J. The display lacks color** 1. Check the data input and output of the color-specific 245 chips. Ensure that the signals are properly transmitted. 2. Test if the data signal for the specific color is shorted to other lines, causing incorrect color rendering. 3. Inspect the cascaded data ports between the driver ICs of that color for any open or short circuits. *Note: Using a voltage detection method can help identify the problem area more easily. Compare the voltage levels at the data ports with normal values to determine where the fault lies.* **K. There is a problem with the output** 1. Check if the output interface connected to the signal output IC is properly connected or shorted. A faulty connection can affect signal transmission. 2. Verify that the clock and latch signals at the output port are functioning correctly. 3. Examine the cascade output data port of the last driver IC to ensure it is properly connected to the data interface of the output IC. 4. Check if the output signals are shorted or grounded, which can cause signal corruption. 5. Finally, test the output cable for any damage or poor connections. A faulty cable can also lead to signal loss or distortion.

Chromium Wear Ball

Steel ball is a commonly used grinding medium with the following characteristics:

1. High hardness: Grinding tool steel ball is usually made of high carbon chromium steel material, high hardness, can effectively grind hard materials.

2. Strong wear resistance: Due to the use of high hardness material, grinding tool steel ball has good wear resistance, can be used for a long time and is not easy to wear.

3. Good compression resistance: After special treatment, the steel ball of the grinding tool has high compression resistance, can withstand greater pressure, and is not easy to deformation or fracture.

4. Good grinding effect: The steel ball of the grinding tool has high grinding efficiency and grinding accuracy, which can quickly and evenly grind the surface of the object to achieve the required smoothness or accuracy.

5. Widely used: Grinding tool steel ball can be used for metal materials, ceramic materials, glass and other materials grinding processing, widely used in machining, electronic manufacturing, chemical industry and other fields.

It should be noted that the appropriate size and material need to be selected according to the specific situation during the use of the grinding tool steel ball to ensure the grinding effect and service life. In addition, pay attention to safety precautions during use to avoid damage to personnel and equipment

Chromium Wear Ball,Abrasion-Resistant Steel Ball,High Hardness Cast Ball,Cast Ball

Xuzhou Surun wear-resistant material Co., LTD , https://www.suruntools.com