I was repairing a miscellaneous LCD TV, and the initial issue was that the indicator light wasn't turning on. After checking the power supply, I found that the 5V rail was normal, but there was no 12V output. Further inspection revealed that two MOSFETs had failed, and one 2A fuse was open. After replacing the faulty components and restoring power, the TV turned on and off normally, with sound working fine, but the image was only visible faintly. This led me to suspect a high-voltage protection issue. Since it was related to high-voltage protection, I started by checking the overcurrent, overvoltage, and open-circuit protection circuits. Upon detailed inspection, I found that D601 and D602 were damaged. Initially, I thought they might be transistors, but after checking the datasheet, I realized they were actually double diodes. The original markings didn’t use "Q" for transistor identification, but instead used "D" for diode symbols. Unfortunately, I couldn’t find an exact replacement for the original A7W25 double diodes. As a temporary solution, I used four BVA21PH diodes as a substitute. After installation, the TV worked properly again. However, I should note that using 1N4148 diodes would not be suitable in this case due to their low voltage rating, which might not withstand the required voltage levels in the circuit. The repair process involved several steps of testing and component replacement, and the final result was successful. Below are some images from the repair process for reference.
Scroll Compressor Series Sealed Terminal Block
Scroll Compressor Series Sealed Terminal Block,Compressor With Bakelite,Co2 Compressor Three-Phase Seal Terminal,Compressor Connector With Copper Cored
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