LG 50PG20 plasma no power issue

[zell66]

got this tv free and wanted to tinker to see if I can fix it. When pluged in no power at all. no red dot nothing. When I try pushing power button no sound at all.

what can I do to see if i can fix this or do I trash it?

[tom66]

Re: LG 50PG20 plasma no power issue

Do you have a digital multimeter available?

[zell66]

Re: LG 50PG20 plasma no power issue

yes i do

[ERICSSON89]

Re: LG 50PG20 plasma no power issue

then start by measuring the voltage on the input PSU connector on the primary hot side with your DMM set to ACV range with the set plug into the AC OUTLET. also check the fuse next to the connector.

[zell66]

Re: LG 50PG20 plasma no power issue

ok you are talking to a newby. lol do you have a scamatic of were the PSU is located or is it labeled on the board? is the PSU the power supply board?

[tom66]

Re: LG 50PG20 plasma no power issue

A good step would be to supply some photos of the chassis and one of each major circuit board, this will help us highlight things for you and understand how it is all connected.

[ERICSSON89]

Re: LG 50PG20 plasma no power issue

tom is the man so do exactly as he instructed.

[ERICSSON89]

Re: LG 50PG20 plasma no power issue

PSU BOARD is power supply board so u need to upload pictures.

[zell66]

Re: LG 50PG20 plasma no power issue

i will do that after work today

[zell66]

Re: LG 50PG20 plasma no power issue

here are some pictures.

[zell66]

Re: LG 50PG20 plasma no power issue

here are the other Circuit boards.

[zell66]

Re: LG 50PG20 plasma no power issue

tom66 if there are other pictures you need please let me know and I will load asap.

Thanks

[tom66]

Re: LG 50PG20 plasma no power issue

This is the power board:
https://www.badcaps.net/forum/attach...2&d=1415654055

Bottom right corner of the board - there's a connector with a legend next to it (indicating voltages and signals like RL_ON, VS_ON, M_ON, etc.), can you get a close up picture of it, OR list what it says?

[zell66]

Re: LG 50PG20 plasma no power issue

tom is this what your looking for?

[tom66]

Re: LG 50PG20 plasma no power issue

Yes thanks.

- Get your meter and set it to the 20V DC range. Do not use the AC range marked with ~
- Put the black probe in an exposed part of the metal chassis of the TV e.g. the wall mount brackets or screw hole works well.
- Plug in the TV. Careful, the chassis is now live, do not touch anything on the power board or sustain boards (left and right of the display panel.)
- Press the red probe against the pin marked "5V" - refer to the legend.
- What do you measure?

[zell66]

Re: LG 50PG20 plasma no power issue

0.00
I used the ground for the power supply and tried to measure the pins marked 5v. I removed the plug in the lower right corner to access the pins.

[tom66]

Re: LG 50PG20 plasma no power issue

Ok. For that test it doesn't matter if the connector is in or not, but it will matter for future tests. You just need to press lightly against the connector block and you can measure with the connector installed.

Are all the fuses on the power board good? To test, use the 200 ohm range, a good fuse will read near to zero, max 3 ohms. The TV -must- be unplugged.

[zell66]

Re: LG 50PG20 plasma no power issue

how many fuses are on the main power supply board?

[tom66]

Re: LG 50PG20 plasma no power issue

I count at least two, possibly there are more if hidden behind or under heatsinks.

[zell66]

Re: LG 50PG20 plasma no power issue

here is were I show my limits. Of the 2 fused is one in the lower left cor. just to the right of the power supply clip?