A customer brought in a 32-inch LG LCD TV, stating that it had lost power after other ports were repaired. It looked like a serious issue. I left a message for the customer and added a note about the situation.
After disassembling the unit, I checked the overcurrent fuse, but it was intact. However, there was no output from the sub-power supply’s +5V rail. This strongly suggested a problem with the power board.
I quickly found a board test machine and confirmed that the power board was indeed faulty. The main IC on the board is an ICE3B0365J, and I didn’t find any obvious damage to other components. Interestingly, when I tested the similar model ICE3B0565 on the same machine, it worked fine.
The TV wouldn’t power up even after being left overnight. I tried replacing capacitors C501, C505, and C503, but the cold start issue persisted. Then, I noticed that the ZD502 (24V) was leaking when removed. I tested it again and confirmed the leakage. So, I replaced it immediately.
After the replacement, the TV started working properly. It was a tricky case, but the key was identifying the faulty component through careful testing and observation.
Used on systems above 1000 volts, protect equipment from lightning and switching surges.
Lightning Arrester,Distribution Pole,Composite Lightning Arrester,Lightning Rod
Jilin Nengxing Electrical Equipment Co. Ltd. , https://www.nengxingelectric.com