The material
LED unit board. In order to compete for low prices, some LED unit board manufacturers use cheap flame-retardant paper boards or single-sided fibreboard as PCB boards for LED lights. Because the fiberglass PCB board is expensive. At the beginning, we can't see the difference. Under normal circumstances, the whole LED unit board will be scrapped due to the breakage caused by damp, ultraviolet damage, oxidation and other reasons within a year. High quality LED unit board must use double-sided all-fiberglass PCB board, although the cost is high, but the quality is guaranteed.
IC device. Observe whether the brands of IC devices used are consistent. What type of IC is used, and how many IC are used, these are enough to affect the quality of LED unit board. Some LED display manufacturers, in order to save cost, will deliberately reduce the number of IC in the production unit board, or mixed with other brands of IC.
Beads and chips. The naked eye cannot distinguish the good from the bad. Only a long time test, what experts call an aging test. The general practice of LED display manufacturers is: before the factory power, check whether the LED display can work normally, will not go through a long time of aging test. Because there's the cost of time and the cost of labor.

02
The welding quality
Check whether the patch is missing or misstuck, and whether there is short circuit of component pin burr. Check whether the welding spot of the straight plug is smooth and round, whether the surface of the board is clean and tidy, no false welding leakage welding. Check the placement flatness and ink color consistency of luminous dot matrix.
03
Electric test
Electrification test (refer to the steps of "Performance Test Report") : The consistency of the luminescence lattice of electrification test; (2) Whether the electrification test can effectively protect the line drive tube CEM4953; (3) Power test signal transmission ability.
Above is about the detection of LED unit board good or bad common method, hope to be helpful to LED display businesses. In addition, quality is the king. Manufacturers also need to reject cheap and shoddy LED display screens, so as to avoid damage to the unit board affecting normal work and subsequent unnecessary maintenance.