내 문제
The display screen in the advertisement board was flickering, and eventually went completely dark. If you can't wait for someone else to fix it, you might as well take it apart and check if the switching power supply is broken.
So how do we determine if the power supply is faulty?
This screen is powered by 12V switching power supply（https://sieconxk.com）. Before it broke, the image was flickering, and the text was dimming and brightening intermittently, until it finally went completely dark. However, the small light on the control card was still faintly flashing, indicating that the control card wasn't damaged. It's highly likely that the power supply was underpowered or completely dead.
The most direct way is to measure the voltage with a multimeter. Locate the output terminals of the power supply (usually V+ and V-), set the multimeter to DC voltage mode. Normally, it should read around 12V. If it reads only a few volts, or 0V, it's basically confirmed. Also, check the power supply casing for any signs of bulging or burn marks.
나의 수리
How to remove and replace it?
Cut the power! This is the most important step – safety first.
Disconnect the wires: Take a photo! Photograph how the original wires are connected, especially the positive and negative terminals. There are many wires inside an advertising screen, and a photo can help you avoid connection mistakes. Then, loosen the screws and disconnect both the 220V input wires (L, N) and the 12V output wires.
Remove the old power supply: The power supply is usually fixed to the back panel with screws; just unscrew it.
Buy a new power supply: Take the old one to an electronics market, or note down the model and buy it online. Pay attention to two key parameters: The voltage (V) must be identical (e.g., if it was 12V, buy another 12V). The current or power (A or W) should ideally be the same or slightly higher (e.g., if the old one was 300W, buying a 300W or 350W one is fine). A higher rating provides more stability, while a lower one won't be able to drive the load.
Install the new power supply: Mount it back in its original position. Take out the photo you just took, and connect the wires one by one according to the photo. Be very careful not to reverse the positive and negative terminals, otherwise, you might burn the LEDs. Also, avoid reversing the 220V L and N connections. While it might still work, it poses a safety hazard.
Inspect and power on: Double-check all connections to ensure nothing is connected incorrectly or loose. Then, turn on the power. If the screen lights up, you're done.
The whole process only takes ten to twenty minutes. Doing it yourself saves a hundred or so bucks on a service call, and more importantly, it gives you a great sense of accomplishment.
내 조언
Repairing it yourself can save costs, help you practice your hands-on skills, give you a sense of achievement when you fix it, and allow you to share the experience with others.
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