Panasonic rear projection TV TC-51P800G boot immediately protect the fault repair example - appliance repair - Huaqiang electronic network

LC03-3.3 SOP8 TVS Static Protection 3.3V

I encountered a Panasonic rear projection TV model TC-51P800G that had a strange issue — it would power on and immediately trigger a protection mode. The first thing I did was to disconnect the cluster line, and after that, the TV no longer entered protection. This strongly suggested that the problem was in the aggregation loop. I removed three sockets from the system and found one of them was completely burnt, while the other two were slightly damp. Replacing all three sockets seemed like a logical step, but after doing so, the TV still wouldn’t turn on. When I checked the acceleration voltage, it only read 80V — which is way below the normal range of over 200V. When I touched the focus, it felt hot, and turning the focus on or off caused the acceleration voltage to fluctuate between 150V and 180V. Touching the high-voltage package also revealed it was extremely hot. When the TV was turned on, the screen showed a very bright red retrace line, which is a clear sign of a faulty CRT. After removing the red tube’s tail plate, I measured the cathode voltage at 70V, which was significantly low. However, the acceleration voltage was around 200V, which was normal. But the tail plate was very wet, indicating coolant leakage from the projection tube. I cleaned the area with banana water and used a hot air blower to dry it thoroughly. After this, the TV turned on with normal brightness. To fully resolve the issue, I needed to address the coolant leakage from the projection tubes. Upon removing all three CRTs, I noticed that the coolant inside each was highly pressurized and bulging. The sealant caps were intact, but the pressure must have been too high, causing the leaks. I carefully removed the sealant covers, allowing the excess coolant to flow out. I then used toilet paper to absorb any remaining liquid before reinstalling the tubes. After reassembly, I adjusted the power settings and fine-tuned the convergence. The TV worked perfectly after that, and the repair was successful.