This PHILIPS LCD TV has a complaint no power. The owner of this tv is the son of my first cousin. He said that while their watching tv, they heard a loud bang coming from inside and the tv became dead. He open it and put another spare fuse and power it again and fuse blown again.It is a sign that there is some shorted component in the switch mode power supply. The model no of the tv is 32PFL3409/98. It is a 32 inch lcd tv.
This lcd tv was bought in abu dabhi in middle east. Upon opening i scan the components for possible clue of burnt and i did not noticed any. So i proceed to usual troubleshooting to test the bridge type diode and it is okay. Second i test is power fet which has a part number K3561 and it is okay also. But i test it also out of circuit to be sure and found it in good condition. So i try to think what cause the fuse to blow if the bridge diode and fet is ok upon scanning i saw high voltage capacitor 1kv 221k a blue color that has dark spot on its body and i noticed it was blown. When you traced it from the positive of the bridge diode going to positive side of main filter capacitor, from that the other pin of switch mode chopper going to the drain of fet but before the drain there is this high voltage capacitor which protect the fet from blowing. I replaced it with 2kv 221J and the Lcd tv came back to life. But before i powered it i test all possible semiconductor that is prone to short like transistor, diode. I test also the optoisolator/ optocoupler. It has power ic FSD510 made by fairchild. It has two power fet K3561 which is not affected by short circuit which protect by two capacitors.
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the second high voltage capacitor which has black spot is the culprit why the fuse blow.
More clearer picture of phillips lcd tv from KKH. Thank you.
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