Today's "Sharp" 26-inch TV is experiencing an issue where the indicator light is red, and pressing the remote control or panel buttons doesn't make any response. Initially, I suspected a problem with the motherboard. The internal components of this unit are as follows:
First, I visually inspected the board for any signs of burnt components or bulging capacitors, but nothing obvious was found. Next, I checked the voltages. The 12V and 5V rails were normal, but the 1.2V rail was reading 0V. I then measured the input voltage to the 1.2V three-terminal IC, which was only 0.7V instead of the expected 3.4V. This indicated a problem in the voltage regulation circuit.
Following this lead, I traced the circuit and found two 1N4007 diodes connected in series. The voltage before the first diode was 5V, but after the diode, it dropped to 1.5V instead of the expected 4.2V.
After further testing, I confirmed that these diodes were faulty. Replacing them restored the 1.2V rail to 3.4V, and the TV started working properly again.
The repair was successful, and the TV is now functioning as intended.
As a small tip, if the high-voltage transistor on the power strip is damaged, you can replace it with alternatives like BUZ91, K2645, 10N60, 12N10, K1117, etc., depending on the specific model.
This kind of repair requires attention to detail and a good understanding of the power supply circuit. It's always important to double-check voltages and test components thoroughly before making any replacements.
MINI FAKRA Automotive Connectors
MINI FAKRA 4PIN Male Connector for Cable,Mini Fakra Connector For Pcb,MINI FAKRA 1PIN Female Connector for Cable VersionA
Dongguan Zhuoyuexin Automotive Electronics Co.,Ltd , https://www.zyx-fakra.com