Hisense LCD TV TLM32V68A irregular timing failure repair - appliance repair - Huaqiang Electronic Network

The phenomenon of TV failure is: sometimes it can be turned on, and the startup process takes a long time after booting. Sometimes, when watching the screen change to a dense vertical bar, the image is not, the sound is not, and the remote control and the panel buttons are invalid. Sometimes the machine can't be turned on, but the blue light on the panel is on (the blue light is on when the power is on and the red light is on when the power is off). Disassemble the machine and visually check that there is no bulge in the capacitors on the high-voltage integrated board. The measurement power supply is normal for 12V and 5V, and the motherboard data is suspected. First measure the power supply voltage of the motherboard, 5V, 3.3V are normal, when measuring a three-terminal voltage regulator N6 (1.2V) near the microcontroller, it feels a bit high, the actual measurement is 1.29V, and the three-terminal voltage regulation is a bit High. The three-terminal regulator model is SE8117TA, which is queried by the Internet as a three-terminal adjustable regulator IC, but the line is viewed. There is no voltage regulator between the three-terminal regulator 1 pin and the 2 pin. Only 1 pin is on the ground. A straight-through resistor. Analysis of the circuit can be directly replaced with AM1117 1.2V three-terminal regulator. In decisive change, the temperature of the three-terminal regulator has dropped significantly, and the measured output voltage of the 2-pin is 1.19V. After several times of power-on and shutdown, there is no crash.


The picture above shows a poor performance three-terminal regulator IC