1. Simple identification of virtual soldering dead lights is a relatively simple but quite effective method of identifying LED dead lights is to heat the lamp that does not turn on. We heated the LED lead of some unlit LED lamp to 200-300 C, removed the source of fire, connected the LED with positive and negative poles by 3-volt button battery. If the LED lamp can be lit at this time, but with the temperature of the lead decreases, the LED lamp changes from bright to unlit, which proves that the LED lamp is virtual welding. The reason of heating energy is that the principle of metal thermal expansion and contraction is used. When the LED lead is heated, the expansion and extension are connected with the internal solder joint. When the power supply is connected, the LED can normally emit light. With the decrease of temperature, the LED lead shrinks back to the normal temperature state. When the LED lead is disconnected from the internal solder joint, the LED lamp will not light up. When this happens, the LED lamp will not light up. The explanation is dead light caused by virtual welding. 2. Simple method to solve LED dead light 1. Solve the damage caused by static electricity to the LED chip, which causes the failure of the PN junction of the LED chip and causes the dead light. Most of the dead lights caused by the failure of the PN knot of the LED chip are caused by the workers themselves. The amount of static electricity in the human body is related to the different fabrics and clothes that people wear and the physique of each person. When we take off clothes in autumn and winter night, we can easily see the discharging phenomenon between clothes. So we should wear anti-static clothes and accessories when we work. Electrostatic rings, electrostatic rings should be well grounded, there is a non-grounded electrostatic rings anti-static effect is not good, it is recommended not to use this product, if staff violate the operating rules, they should receive the corresponding warning education, but also play a role in warning others. 2. One of the links in the packaging process is negligence, which is mainly caused by the negligence of the staff. If the staff accidentally points more or less silver glue (for single solder chip), it will not work. More glue will return to the gold pad of the chip, resulting in short circuit, less chip and sticky. Welding process, the temperature is generally 280 C is the best, the pressure, time, temperature, power of the four parameters of the golden wire ball welding machine should be properly matched, otherwise, high pressure is easy to crush the chip, too small is easy to virtual welding.