LG 42PJ550 Plasma Problem

[LGM]

Good Day!

My LG Plasma seems to have stopped working yesterday after a thunderstorm rolled through the area.
My step daughter was watching TV at the time, and said there was a loud thunder-bang, and then the plasma stopped working. Personally, I think the TV had enough of the torture perpetrated by MTV and committed suicide, but I digress.

It's a 42" model, manufactured in May 2010.

When power button is pressed, 2 quick clicks, screen "brightens" (grey screen, hard to tell in a bright room that it's lit) then after about 2 seconds goes to black (no click).
The red power LED on front of display doesn't do anything (on this model the red LED comes on when the power is off or a button is pressed).
Internally, there is a small LED on a circuit board labeled D101 that flashes green. 2 short 1 long, 1 short 1 long.

I have left the unit unplugged for about an hour and tried cycling through the power, with the same results.

I took off the back cover to look for blown caps, but all the caps I could see look fine, no bulging.

Any ideas?
Thanks in advance.

[tom66]

Re: LG 42PJ550 Plasma Problem

Can you share some pictures of the TV's chassis?

[retiredcaps]

Re: LG 42PJ550 Plasma Problem

Personally, I think the TV had enough of the torture perpetrated by MTV and committed suicide, but I digress.

[LGM]

Re: LG 42PJ550 Plasma Problem

Are these pics ok?

[tom66]

Re: LG 42PJ550 Plasma Problem

Try uploading them using the Manage Attachments feature. Yours have come out too small.

[LGM]

Re: LG 42PJ550 Plasma Problem

See if this works

[tom66]

Re: LG 42PJ550 Plasma Problem

Can you upload bigger images or go closer to this board:
https://www.badcaps.net/forum/attach...3&d=1369869069

I need to see if there is a test mode jumper on it.

[LGM]

Re: LG 42PJ550 Plasma Problem

How's this?

[tom66]

Re: LG 42PJ550 Plasma Problem

Great -- see the points marked EXT AUTO GEN?

Unplug the TV.

Take a piece of wire and connect the two holes.

Unplug the top middle cable in this image.
https://www.badcaps.net/forum/attach...4&d=1369870445

Turn the TV on. You should see test patterns, do you?

[LGM]

Re: LG 42PJ550 Plasma Problem

Yes, the test patterns are showing.

[tom66]

Re: LG 42PJ550 Plasma Problem

OK, the fault is on the main board. Someone else had this problem a few weeks ago after a power surge too, on the same model. (Zenith brand but same TV.)

Is there any chance you could upload a video of the test patterns for other users to compare against in the future? (You could upload it to YouTube or send me a copy and I will upload it.)

[LGM]

Re: LG 42PJ550 Plasma Problem

It ran the test pattern for about 15 minutes and then shut itself off.

[tom66]

Re: LG 42PJ550 Plasma Problem

That is normal, after some time the main board shuts off due to no signal.

[LGM]

Re: LG 42PJ550 Plasma Problem

Sure thing Tom, I'll record the test pattern and figure out a way to get it to you.
Regarding the main board fault; do you know if this could be a component level repair or does the mainboard need replacing? And if the mainboard needs replacing, any idea on cost?

Thanks for the help!

[tom66]

Re: LG 42PJ550 Plasma Problem

It's pretty much a replacement job. Most of the components on that aren't readily available. As for cost, the Z42PJ240 (Zenith) guy got it for $28, so you might expect a price around that area -- the boards are used, pulls from scrap TVs, so prices vary (buying direct from LG would be $150+ typically.) Places to buy include ShopJimmy, eBay, etc.

To order the board look for the EAX, EAY, ERB or EBR numbers, in that order (EAX better than EAY etc. as far as specific-ness goes.) Then, search for that number on parts websites and find a low price with a returns policy. (This is pretty critical because you can get dud boards.)

[LGM]

Re: LG 42PJ550 Plasma Problem

Thanks for the help Tom.

The video file was 44m, so I checked Youtube to see if anyone else had uploaded it.

It is pretty much the same as this: http://www.youtube.com/watch?v=soZ9jblKBpE

[LGM]

Re: LG 42PJ550 Plasma Problem

Last quick question, for tonight anyways

Is the mainboard the same board that you had me jump the connection and unplug the connector?

Thanks

[tom66]

Re: LG 42PJ550 Plasma Problem

It's just a request, as I haven't yet been able to work on a modern LG plasma (I've worked on three older ones), otherwise I'd make it myself. Oldest I've got my hands on is a 2007 panel. LG are popular wiht repair guys so they go for high prices (in part due to high parts availability & premium appeal I expect. They aren't too badly made. Not the best, but better than Samsung...) Interesting that the pattern is similar I guess LG wouldn't change a recipe that works well...

[tom66]

Re: LG 42PJ550 Plasma Problem

Last quick question, for tonight anyways

Is the mainboard the same board that you had me jump the connection and unplug the connector?

Thanks

The main board is the board with the video inputs on it (HDMI etc.) The board you did the jumper on is functioning. It is the control board or PDP T-CON.

[tylerh1994]

Re: LG 42PJ550 Plasma Problem

Hi there, I have the same TV and my screen has gone blank.

I have tried the test listed above, but my screen is still dark and blank.

Any suggestions what to try next to determine my faulty component.

Background: For a month or more, I would have to turn on my TV 2-3 times to get a picture. I get the double click on power up, obviously there is an error detected and its shutting off the screen.