What causes some LED beads in an LED stadium light to not light up?
LED stadium lights typically consist of multiple LED modules (each module containing dozens of LED beads). If some beads are not lighting up, common causes include:
First, a single LED bead is open-circuited (burned out). In a series circuit, an open circuit in one bead will cause the entire string to not light up. Visually, black spots or burn marks can be seen on the unlit bead. Solution: Replace the damaged bead (requires a hot air gun and soldering skills) or replace the entire module.
Second, loose or oxidized connectors. Modules are usually connected by waterproof connectors; poor contact can cause partial power outages. Re-plug or replace the connector.
Third, a failure in one output channel of the driver power supply. If the driver has multiple outputs (e.g., 4 independent constant current channels), a failure in one channel will only cause the corresponding group of LED beads to not light up. Use a multimeter to measure the output voltage of each channel of the driver. If any channel is zero, the driver is damaged and needs to be replaced.
Fourth, corrosion or breakage of the aluminum substrate circuitry. In lamps where moisture enters, the wiring may corrode, causing an open circuit. The aluminum substrate needs to be replaced.
Fifth, electrostatic discharge (ESD) damage. During repair, ESD can cause the LED beads to break down, leading to failure. An anti-static wrist strap must be worn during repairs.
Sixth, poor soldering of LED beads. Poor soldering during manufacturing can cause them to detach due to thermal expansion and contraction. Resoldering will resolve the issue. When some LED beads are not lighting up, it is recommended to first check if the driver output is normal, then check the connector, and finally check the LED beads themselves. If more than 10% of the LED beads are damaged, it is generally recommended to replace the entire module or lamp, as replacing each LED bead individually is time-consuming and reduces reliability.
