Solution: (1) LED control card parameters are set correctly Linyi led unit board, there is no signal is transmitted to the electronic display LED control card; (2) communication lines are communicating properly Ningxia led unit board, LED control card view if there signal input; (3) LED control card 5V power supply is normal; LED light emitting device performance of LED light-emitting display device is the most critical and most relevant parts and life. For LED, mainly the following indicators: attenuation characteristics, water vapor permeability, UV resistance. If the LED display manufacturer LED device performance indicators for the assessment, but off on the application to the display, it will cause a lot of quality accident, seriously affecting the life of the LED display. Chengdu led unit board | Gao Jin photovoltaic (certified) | led unit board provided by Jinan Optoelectronics Technology Co., Ltd. Gao Jin. Jinan Gao Jin Optoelectronics Technology Co., Ltd. (www.gjlled.cn) is an industry leader in Jinan, Shandong, liquid crystal devices, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In Gao Jin photoelectric leadership with the staff warmly welcome all inquiries negotiations to create high gold Photoelectric better future.