In July 2010, I received a repair request from a Thomson customer. The issue was that their Thomson TP4312D projection TV wouldn't turn on. From my experience, there are usually two common scenarios: either the power indicator is on but the TV doesn’t start, or there's no power at all, with the indicator off and no response. After contacting the customer, they confirmed that there was no power display and the TV didn’t turn on at all.
Based on my previous troubleshooting experience, this could be related to the power supply or the system control unit. When I arrived on-site, I checked the power supply and found that the +5V output was normal, as was the CPU power supply. However, when measuring the static resistance, I noticed that the resistance on the CPU and RAM address lines was unusually low. Replacing the RAM didn’t resolve the issue, so I suspected a problem with the CPU itself.
The CPU in this model is a surface-mounted component with a very thin copper foil layer underneath. Soldering it requires precision and timing—too long, and the board could be damaged. I carefully removed the peripheral components, desoldered the old CPU, and replaced it with a new one. After re-soldering, cleaning, and drying, the TV powered on normally. The boot screen appeared, and both the image and sound were working perfectly.
This case reminded me of some important tips for similar repairs. First, always be cautious when soldering surface-mounted CPUs. The copper layers are delicate, and improper technique can easily damage the board. Second, avoid applying excess solder near other components, as this can cause short circuits. Since the CPU is close to other parts, even a small mistake can lead to bigger problems.
Although I have been working with Thomson products for many years, I still feel that there’s always more to learn. If anyone is interested, I’d be happy to discuss further with the CSC team. I believe that sharing knowledge helps everyone grow.
However, I want to express my disappointment regarding some recent incidents. A few years ago, a repair shop called Hongsheng tampered with and copied my work without permission. This kind of behavior not only undermines trust but also discourages people from sharing their experiences. I strongly condemn such actions. If this trend continues, it will harm the community and discourage genuine contributions. Everyone should respect the effort and time put into these shared resources.
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