lg 55 inch model 50pg20ua wont turn on

[daryck88]

hey im new here and in need of sum help i have this tv and when i turnd it on the other day heard a pop noise and now it wont come on at all.so i opend it but am not to familiar with it and found a power supply board with not sure of the name but they look cylinder things bulging and sum have black marks not sure if this could be the problem though.if any one knows please help thanks....

[Jasgriff]

Re: lg 55 inch model 50pg20ua wont turn on

Hi,

Welcome to the forum.

They are more than likely capacitors. To help you we will need some good pictures top down of the board. Clear enough the the writing can be read.

It might be a good idea to tell us the writing on each of the capacitors exactly and let us know which ones look bulged.

Can you solder?

[tom66]

Re: lg 55 inch model 50pg20ua wont turn on

With these LG TVs two things go wrong:
- Bad caps
- Sustain boards

If you heard a loud pop while trying to turn it on, you need a new Y or Z-sustain board. Or you can replace the IPM on the Y or Z-sustain board, however that does require good soldering skills.

If you also have bulging capacitors then these are simply due to age and were going to cause a problem eventually... you just happen to have caught them now. So it would also be advisable to replace those caps. LG used cheap capacitors on their TVs that only lasted a couple of years.

Do you have a digital multimeter?

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

well i was thinking about just replacing the whole board because i dont have a soldering gun or a mulitmeter im an electrican and all i have is an electrical tester. i was just wondering if this board was where the problem is at or if sumthing else made this board blow the capacitors.the model number on the board is lpx55 and the writting on the capacitors says samwwa wb
10 v
3300 um
105c(m)
and four of them are bulging and two of them have burn marks.
and it made the pop noise while we were watching t.v.

[tom66]

Re: lg 55 inch model 50pg20ua wont turn on

well i was thinking about just replacing the whole board because i dont have a soldering gun or a mulitmeter im an electrican and all i have is an electrical tester. i was just wondering if this board was where the problem is at or if sumthing else made this board blow the capacitors.the model number on the board is lpx55 and the writting on the capacitors says samwwa wb
10 v
3300 um
105c(m)
and four of them are bulging and two of them have burn marks.
and it made the pop noise while we were watching t.v.

I have about 13 Samwha WB capacitors in my bag of bad capacitors; they are absolutely rubbish and fail without apparent cause.

A cheap multimeter costs $3 and will be enough to use to debug the power supply and sustain boards.

You don't want to just replace the Y or Z-sustain as you can't be certain which one it is yet.

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

so replacing the power board completely wont fix the problem.sumthing eles cause the caps. to burst? cause i have no power to the tv at all not even the light on the front.

[tom66]

Re: lg 55 inch model 50pg20ua wont turn on

so replacing the power board completely wont fix the problem.sumthing eles cause the caps. to burst? cause i have no power to the tv at all not even the light on the front.

Nope. The capacitors failed because they were poorly made. Replacing the capacitors with high grade replacements (in my case I used Chemicon and Nichicon), costing less than $1 each will mean the capacitors will last beyond 10 years.

Start by disassembling the TV and taking detailed pictures of the insides.

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

im not too good at uploading pics on the computer and posting them but if i can have some one i know help me i will asap.but for the tv ive already opened it and looked it over the only problems i see are the blown and buldging caps. on the power board every thing else looks and smells fine....

[tom66]

Re: lg 55 inch model 50pg20ua wont turn on

The fuse on the Z- or Y-sustain is likely blown, but you'll need a multimeter with an ohm setting to test it. Do you have one?

[Jasgriff]

Re: lg 55 inch model 50pg20ua wont turn on

im not too good at uploading pics on the computer and posting them but if i can have some one i know help me i will asap.but for the tv ive already opened it and looked it over the only problems i see are the blown and buldging caps. on the power board every thing else looks and smells fine....

Also take a read of this see if it helps you understand how to do you pictures.

https://www.badcaps.net/forum/showthread.php?t=19629

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

im an electrican so i have an electrical tester a fluke t5-600 i know it lets you test continuity but to see if fuses are good but not sure how to check ohoms

[retiredcaps]

Re: lg 55 inch model 50pg20ua wont turn on

im an electrican so i have an electrical tester a fluke t5-600 i know it lets you test continuity but to see if fuses are good but not sure how to check ohoms

A good fuse will measure less than 1.0 ohms. So your T5-600 it should show 0 or 1 ohms because the resolution is a single digit.

More info from another thread usinga T5-1000 at

https://www.badcaps.net/forum/showpo...0&postcount=33

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

so today i went to an electronics store and bought sup caps and fuses to replace the bad ones that i noticed were bad and put them in and when i pluged it in i heard a click noise and still have no power. so i checked the fuses i replaced and foud that one of them popd again.its located on the power board and is labeled 250 VOLT T5AH MODLE NUMBER OF THE POWER BOARD IS LPX55.sorry for the pics now im looking for the cable to charge my camera.

[daryck88]

Re: lg 55 inch model 50pg20ua wont turn on

here are the oics of the power board