During a recent repair of a TCL LCD TV model L32E5200BE, the power indicator light was on, but the standby button failed to turn the TV on. After checking the power supply board, it was found that the 3.3V output was normal, and the 24V output was also stable. To further diagnose the issue, the 24V output from the power board was forced to start separately. Upon observation, the 24V voltage was supplying both the backlight board and the motherboard. A dummy load was not connected to the backlight board during testing. When the motherboard was connected to the power line and the power button was pressed, the indicator light turned on, and pressing it again turned the light off. This indicated that the power board was functioning properly, and the issue was likely with the backlight board.
To confirm the problem, the P3506DD transistor on the backlight board was tested, and an 18N20 field-effect transistor was found to be damaged. Since no spare parts were available at the time, the entire backlight board was replaced to restore the TV’s functionality. The repair process involved careful testing and component analysis, highlighting the importance of systematic troubleshooting in electronics repair. Below are some images taken during the repair for reference.
Three Phase Ammeter,Voltage Ammeter,Three-Phase Power Meter,Power Instrument
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