LCD maintenance entry: saying that there is no technical content to replace the main chip - android - Phones Developers

The main chip replacement on an LCD motherboard is often the root cause of failure. Fortunately, modern LCDs are simplified and mostly rely on "microcontrollers," making fault diagnosis much easier for technicians. There's not much technical complexity involved—just proper tools and careful handling. Many experienced individuals know how to do it, but it still feels like a bit of a mystery. Tools I use: My hot air station is from a domestic brand, and I consider it essential for SMD rework. It's more than 400 yuan, but it’s worth it. A good brand ensures stable temperature and prevents burning the hot head. I’ve used cheaper brands (around 40 yuan) that aren’t as reliable. The 60W temperature-controlled soldering station (936 yuan) is great—it heats up quickly, has a good tip, and lasts longer. I prefer the Quick brand, which costs around 15 yuan. It’s perfect for daily maintenance and can last 2–3 years. Some models are noisy, but they’re still functional. I also use a 5-yuan soldering iron for basic tasks. For BGA work, I sometimes use solder paste instead of rosin, which is less smelly. Even at 8 yuan, you don’t need to worry about precision. Not all cheap tools are bad—some 10-yuan or 5-yuan items are actually quite good. Don’t settle for subpar equipment. I also use a 10x magnifying glass for cleaning with Tian Na water (or any similar solution). Here’s a picture: I’m pretty aggressive with the heat. This chip requires temperatures over 400°C. There’s a heat sink on the bottom of the chip. Before starting, make sure the heat sink is properly grounded using a tin knife or tin strip. Treat the pad with a clean tin strip to ensure a flat surface. If you don’t have a tin strip, you can use a knife to flatten the area. The surface must be smooth, without any raised solder. Once aligned, the chip should move freely without sticking. If the tip is damaged, replace it immediately to avoid damaging the PCB pads. After aligning the chip, secure it with tweezers and evenly apply heat with the hot air gun. Slowly swing the heat over the center until the solder melts. The heat sink should be fully melted in about 25 seconds. Once the heat sink is in place, if the alignment is correct, the soldering should be straightforward. But if it’s off, removing the solder becomes a nightmare. You may need to reheat and start over. Final step: Use a sharp tool or a scorpion tip under a magnifying glass to check all the pins. If any are poorly soldered, they’ll shift slightly under the lens. In that case, reposition the pin and resolder it. Finally, touch up the remaining pins with solder. There are several ways to separate the solder: 1. Use flux to melt the existing solder. 2. Apply a tin strip. 3. Clean the soldering iron tip and use surface tension to guide the solder. I skip the gravity method, just ensuring even heating across the board. The flux should dry before it burns. Only after following these steps can you achieve a clean, professional result. Always use quality tin, not junk. If there’s a heat sink on the chip, grounding is crucial. For simple fixes, the foot alignment step might be skipped. For small chips like a DVD player, using a tin strip can eliminate the need for drag welding. Just remove the old chip with the hot air gun, align the new one, and let the surface tension do the rest. It takes about 2 minutes for an expert, but I took over 10 minutes for this one.

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