LG 32LS4600 no power

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One day my wife went to watch TV when it went BANG!

I haven't plugged it in since but on the weekend I pulled the back off to take a look at the power supply. The Fuse closest to the power plug is blown.
I have check all diodes and resistors while in circuit (not ideal), none are shorted or open.

Is there anything else I should check before replacing the fuse?
I was at least thinking of replacing the samyoung capacitors to help it live a bit longer.

[vinceroger69]

Re: LG 32LS4600 no power

have you tested the bridge rectifier bottom right of first picture.

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Re: LG 32LS4600 no power

You mean the bottom left? Yes that seems to be fine 0.57v on the diode test

[vinceroger69]

Re: LG 32LS4600 no power

yes thats the one sorry i got left and right mixed up also next to the mains fuse there sa device hidden by shrink wrap tube does that test ok? also maybe if you havnt got one already build your self a dim bulb tester that way it will save you blowing fuses and any new parts etc.

[diif]

Re: LG 32LS4600 no power

There should be more than one diode measurement when testing a bridge rectifier.
Is the thermistor ok ? it might just be the photo. Next to the fuse marked TH101.

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Re: LG 32LS4600 no power

Thank you both for replying.

Yeah there were multiple measurements for the bridge rectifier, both measured 0.57v on the diode test on pins 1 and 2, then the same for 3 and 4. Reversing the polarity gives me OL.

I'll check out the thermistor when I get home tonight. It looks like the easiest way to test will be to take a reading at room temperature, then heat it up and compare the readings?

I think i'll be making a dim bulb tester (I'll get multiple uses out of it I think)

[diif]

Re: LG 32LS4600 no power

There's four diodes to check in the bridge rectifier.
Check the thermistor visibly (mine was cracked) and it's not shorted.

They were the two failed items in a similar power supply I repaired.

[budm]

Re: LG 32LS4600 no power

What resistance do you get reading between the two outer pins (pin 1 and 4) of the bridge?

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Re: LG 32LS4600 no power

What resistance do you get reading between the two outer pins (pin 1 and 4) of the bridge?

This may be because it's in circuit, but I sometimes get a reading of 175k ohm and sometimes it's 7M ohm. Sometimes it starts out at 1 or 2M ohm and climbs up to 7M over about 10 seconds or so?

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Re: LG 32LS4600 no power

There's four diodes to check in the bridge rectifier.
Check the thermistor visibly (mine was cracked) and it's not shorted.

They were the two failed items in a similar power supply I repaired.

Both the thermistor and varistor near the #1 fuse seem ok, they are not open and not shorted (thermistor is in spec according to its data sheet)

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Re: LG 32LS4600 no power

OK I found the issue.
A hairline crack that opened right up once i bent it a bit.
I'll replace this and the fuse and re-test.

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Re: LG 32LS4600 no power

Took a while to get the parts but replacing the fuse and the ceramic capacitor did the trick.
I also rigged up a dim bulb tester, so that will come handy in the future!

Thank you everyone for your help.