sir, May I know how to test “KIA78R09PI”. There is not output voltage
from the mentioned ic on the PCB of TV. and I can’t understand to
test it. please show some ideas to test it. hope lots of help comes.
This is a 4 pins Voltage Regulator IC. It has an additional control pin and the signal usually coming from MCU IC to trigger the IC so that there will be output. If there is no signal to the control pin this means there will be no output. The first thing to check, the IC must have DC input first. You need to locate the datasheet in order find out the control pin. If there is an On signal (usually few volts) to the control pin and if the input dc voltage is presence and no output voltage then direct replace the IC. If the load has something shorted, it can also cause the output line voltage to drop. This also means you need to lift up the IC output pin and test. If still no output voltage then the IC indeed is faulty and need replacement