How to test KIA78R09PI

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.
thanks

 

Reply:

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

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TL431 Test

Dear Jestine,

Please I have a small problem and I need some advice.
I have a faulty TV with a faulty power supply. When I checked one of the output 3 legs IC1431T ,with coponent
analyser it gave the folowing result,
NPN DARLINGTON TRANSISTOR
COLL EMIT
DIODE PROTECTION BETWEEN C-E
RESISTOR SHUNT BETWEEN B-E HFE NOT ACCURATE DUE TO  TO B-E RES
CURRENT GAIN .
HFC=1452
TEST CURRENT
IC=2.50Ma
BASE-EMITTER V
VBE=1.54V
TEST CURRENT
IB=3.78MA
LEAGAGE CURRENT
Ic=0.00mA

Because the tester indicated HFC is not accurate,I decided to buy one. I was given IC FAN431 as the same as mine. When I tested it with my component analyser it did not give any readings.
The only information that came on the screen is NPN Transistor.

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How To Test A Diode

Hi Sir. Jestine,

Is it okay I got 2 readings in diode SR204? Noted to the pictures that I have sent to you. Please help me and thank you in advance.

A.P

test diode

Reply:

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