lg model 50pg20ua no power at all

[daryck88]

so my tv mad a pop noise when watching it and completely lost power.so i opend it up and noticed sum capacitors buldging with burn marks on the top so i replaced them and a fuse that had no continuity so i replaced it.put every thing back together pluged it in and the fuse i replaced pop again but the capacitors were fine. so today i replaced the fuse again and unpluged every thing from the power board and pluged it in again and the same fuse poped.the model of the power board is LPX55 and the fuse is labeld 250 VOLT T5AH.PLEASE ANY HELP WOULD BE GREAT....THNKS.....

[Jasgriff]

Re: lg model 50pg20ua no power at all

Hi Daryck88,

The Fuse normally blows when something has failed. If it keeps blowing then its definitely something other than your capacitors that are at fault.

To help you out we would need some pictures of the back of your tv and then some pictures or the top and bottom of your power supply. These need to be really clear so that we can see traces and wording.

Do you have a Mulitmeter also?

[Jasgriff]

Re: lg model 50pg20ua no power at all

I see that this is a double post?

[daryck88]

Re: lg model 50pg20ua no power at all

yeah the guy i was talking to hasnt replied in a while and im new here so im not real familiar with navagating aroud.

[selldoor]

Re: lg model 50pg20ua no power at all

Hi pictures are not really clear enough - they need to look like this
https://www.badcaps.net/forum/attach...1&d=1290283049

If necessary take the board outside or near a window - plenty light but no flash or
glare is the answer.

When you say you replaced the caps what make are the new ones? are they the same
values as those removed? are you sure you put them in the right way round?

Hopefully the board was not on a conductive surface when you re tested.

Can you test the Bridge rectifier see Youtube http://www.youtube.com/watch?v=dqkT6hF0O3E

[cadiman]

Re: lg model 50pg20ua no power at all

When the fuse blows on the input voltage (120vac) you need to go after the bridge rectifier (as said above) and mostly the mosfets that are directly after it or a shorted transformer.
You will find on the primary side of the power supply these will short (on) and thus making a direct short and popping the fuse.

The fuse most likely pops as soon as the tv is plugged in.

[daryck88]

Re: lg model 50pg20ua no power at all

do i have to un solder each piece or can i just test it while on the board?

would it be best if i just replace the whole board with a new one?

an the caps i replaced are completely identical to the ones i took out.negative and positive are on the correct side and when i what to put power again the power board was mounted bact in the tv.

[selldoor]

Re: lg model 50pg20ua no power at all

do i have to un solder each piece or can i just test it while on the board?

You can test in circuit if any look failed it is then best to remove and re test

would it be best if i just replace the whole board with a new one?

That is your call ,but unless you buy a NEW guaranteed one is it going to be any better and how do you know it is which board is at fault?

an the caps i replaced are completely identical to the ones i took out.negative and positive are on the correct side and when i what to put power again the power board was mounted bact in the tv.

ok - but what make were they?