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LCD: White became purple, green became black.

Last response: in Graphics & Displays
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August 20, 2012 6:18:35 PM

Hello guys.

The green color in my lcd is now black (none). Which makes white - purple.
It`s from the bios, not related to settings antwhere in the pc, so it is with other computers tested.

The only thing I find peculiar is that when it displays internal messages (lcd`s) like : "power saving mode" or the LG loading screen, it seems to have white.

Now I see that when I play with the settings of the monitor itself, I can change the appearance to be less purple and even display green, but then the green is very high on contrast. The menu itself displays all colors well, including green and white.
But after resetting to factory defaults, white becomes purple.

Any suggestions to what parts might be involved. I preffer to fix it myself if possible.

Thanks for any help.
August 20, 2012 7:51:38 PM

look like you gone need another lcd this one is going outtry it on another system and if it does the same start looking for a new one
August 20, 2012 8:15:10 PM

Same thing on another system. Same, if different cables.
No replaceable parts?
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August 20, 2012 8:18:24 PM

if you have the kwonledge you could try but it will cost around the same price as a new one without warranty that the repair will work and last
August 20, 2012 9:45:58 PM

It's likely that an external interface chip is screwwed up, the panel itself is fine. Are you using VGA right now? It sounds like you tried different cables, what about a DVI or HDMI cable or something?

If trying different cables and cable types doesn't work, you'll likely need some serious soldering skills to replace what is likely to be a surface mount chip that will be tough to find a replacement for (I've never cracked open a monitor, just guessing from general electronics experience).

If you do open your monitor, try to follow the traces from where your connector comes into the monitor to the first IC chip you see, look up it's part number and see what it is; see if that makes sense to be the possible culprit; rinse and repeat till you think you found something that could be the culprit (Digital or analog signal decoder chip).

August 21, 2012 8:52:36 AM

DVI VGA, other systems - all the same.
Here`s an image of the first circuit board. Note that it`s an old one, I took it when I opened it 2 years ago, so you won`t see any defects, if there are any.



http://s12.postimage.org/ct0qswep9/DSC00373.jpg (same)

After playing with the monitor options:
Now I can see some green, after playing with the options but it`s still all pinkish white, and strange.

Best solution

August 21, 2012 12:14:44 PM
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First off, it's extremely troubling to see the words "TEST BOARD" are somehow still being printed on a piece of production hardware.

That does seem like the most obvious place to start if you wanted to try replacing hardware; because the LCD panel displays it's menus fine, it means that when it's micro-controller outputs is able to output video to the monitor properly (and I would expect you can find another chip similar to that big one that's all stickered up somewhere on another board).

First things first, try reseating the 3 connectors pictured (and at the other ends of each connector) be sure to guard against ESD; make sure none of the wires are mangled or anything.

You maybe able to try calling LG and requesting the part you've got pictured, I'm inclined to believe the part number is 79E12580; if they are actually willing to help you get a replacement for it, they should be able to help you determine which number is the part number. However, more than likely you'll get a "sorry, you'll have to buy another one".

If you aren't getting much help on replacement parts, I'm going to say you're pretty much out of luck. You can try looking for bad/shorted solder joints or bulging capacitors; if you're feeling really ambitious you can try replacing the clock crystal (the silver oval shaped guy directly in the center of the board) but I wouldn't give that effort much hope myself.

You can try googling around for similar problems to yours, sometimes you'll find you're not alone with problems like this and someone has published a how to on fixing the issue.
August 30, 2012 8:59:48 AM

Thanks for the suggestions and manual (didn`t have it).

Scribbles, it seems like too much and too gentle for me to handle, I`ll give it to a shop and post the results here, if any.

Thanks.
September 2, 2012 8:59:13 AM

Best answer selected by ZKR.
September 2, 2012 9:28:30 AM

This topic has been closed by Mousemonkey
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