Remove the lampshade after the power, see which lamp beads are not bright, may be one or N, it does not matter, use a pen to mark. Be safe when the power is on. After finding the lamp beads that are not bright, use the pliers to pull off the lamp beads that are not bright, and pull out a few, after pulling out, you will see that each lamp bead has two connection points. Be careful not to scratch the board.
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Use a wire instead of a lamp bead, prepare the wire 4-5cm, peel both ends and pay attention to the length 3-5mm, and connect the mule iron to the power supply for heating. When the above work is ready for welding, the two ends of the wire are welded to the two contacts. Be careful not to burn your hands while welding. By this time the work is done, and the brightness is restored to the previous level.
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Because the lamp beads used on the lamp board are in series, when a lamp bead or more lamp beads are not bright, the resistance is very large, so it can only emit weak light. This will happen: the 18 watt led light is not on the 5 watt light.
LED lamp beads broken can be replaced with a resistor. Resistance value R=U\/I. Where, U is the normal working voltage of the lamp bead, and I is the current when the lamp bead emits normally.