Wednesday, February 16, 2011

LG DU-42PX12X Plasma TV Fix



An acquaintance of ours was getting rid of their LG DU-42PX12X Plasma TV because it had colored bars down the sides.
I consider myself fairly handy when it comes to fixing things,
So I picked it up before they could thrown it out.
This picture isn't very good,
But it had green and red bars,
Occasionally some blue,
Of varying thicknesses,
But usually an inch or more.
A quick Google for the terms "fix plasma tv", turns up this Youtube.

Don't do this.
That's just stupid.

More googleing lead me to then owners manual.
Further use of my mastery of Google Fu turned up this article.
User kdawg22 talks about how he has fixed this problem on th
is specific model multiple times.
He says the issue faulty soldering on the Main Logic Board.
I eventually found Service Manual.

Through more googleing I pieced together that the Main Logic Board looks like this.
Page 15 of the service Manual identifies part as 201 on the diagram on page 14.
It also gives that part number as 6870QCH003A.


Armed with this knowledge,
I dove into the TV.
First I removed the access panel (401 on the exploded view).
This didn't look like the images I found,
And a closer look at the service manual indicates that the main logic board was under these boards.
It became clear that I had to take the main case off (part 400 on the exploded view).
There were screws lining the edges as well as a few scattered in the middle.
There were four screws holding a panel that had the two boards that were visible from the access panel (parts 402, 420, & 560 on the exploded view).
These boards are the inputs for the TV.
In order to take the panel that holds these boards off,
You have to remove the stand (part 430 on the exploded view)
Lat the TV on its face.
There are four big screws that hold it in.
After taking the stand of I left everything plugged in and flipped the panel upside and screwed it into several other holes.
It then reattached the stand and stood the TV back up.
This allows access to the main logic board (part 201 on the exploded view)
All those small chips in a row at the bottom of the board are the ones that control the screen's X axis.
This is where the solder came lose.
I found that by powering up the TV with all the panels open and pressing on the chips on either end of the row,
I could make the vertical bars disappear.
I tried useing a heat gun to melt the solder,
Hoping that would reset the connections.
This didn't work.
We ended up buying a new board.
Since this TV is beyond it's service life,
Parts are hard to find.
We were able to find the board through Amazon.
From this point everything was just put together in reverse order.

It seems to work just fine.

5 comments:

  1. i just found one of these same exact model in the garbage but half screen is black little 50% of the screen is black but other half shows video would this board fix problem i tried pushing on board it had redline and i reflowed board and it got rid of line but now half screen dunno

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  2. This is the nice post and this post is really appreciable and useful.I like this post and appreciate you for your experience sharing.If you are looking for the Plasma TV Install | Plasma TV Installation | Plasma Installation

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  3. This board has become available again on Ebay and slightly cheaper from the same seller here: http://www.6871qch038a.com/
    They show pictures of the problems it will fix and pictures of problems it will not fix. My Vizio plasma uses the same board and I was able to fix it for about $90 including the shipping cost.

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  4. Have a 50" plasma, LG 50PK750 bottom half black top very good picture.
    Research says that this can be either R or L top or bottom, each controlled by a SUS board on my TV the sus board was on left side bottom and R and L on the right side.
    Using the part # purchased the particular sus board on e-bay, slight difficulty removing ribbon connector (must be pinched lightly) to remove also removed all screws except 1 to allow the board that was connected by the ribbon cable to allow it to be lifted up to remove and replace the sus board.
    tuned it back on all working again.
    George

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