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Old 08-13-2013, 11:30 PM   #1
70JUDGE
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Default Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

I have a Samsung LN46A540P2F LN46A540P2FXZA LCD TV that has randon flashing multicolored horizontal lines on the left side of screen.The lines pick,and choose when to appear.Sometimes when I first turn the TV on,sometimes it takes awhile.They are always on the left side,and they don't go any further then halfway across the screen.Before replacing the capacitors,the horizontal lines are were mostly red,and didn't go very far across the screen.After replacing the capacitors, and the T-Con board,the lines changed to different colors,mostly black,and would go further across the screen when they wanted to.

When I bought the TV from the original owner they said Samsung replaced a board (Power Supply?) which fixed the TV for a couple of weeks,only to have the same problem return.Samsung then told them the panel was bad.

Since I have owned it,I have changed the capacitors in the BN44-00202A power supply that were know to go bad to a better brand/series.I left the smaller capacitors,as they tested good ESR.In fact,all the capacitors tested good.I could tell the original capacitors were changed by someone to a Sam Young brand.I read online where someone had changed their power supply,and it fixed the line probelm.For how long,I don't know.

I also changed the T-Con,but the lines still appear.Did I get a bad T-Con board with the same problem?When I looked up the T-Con board number LJ94-02539A,it doesn't match up with my model TV.It shows a LN46A580P6FXZA.I tried cleaning the ribbon contacts that go into the T-Con board,but that didn't help.I couldn't get to the contacts that go into the panel side.Do I have a bad tab bond?

Any help is greatly appreciated.

Thank You very much!

Tyler
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Old 08-14-2013, 12:43 AM   #2
capkid
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

Pics of the issue you're experiencing onscreen might be helpful.
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Old 09-13-2013, 10:45 PM   #3
70JUDGE
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

I just turned the TV on tonight to see if the lines appear in the menu,and they do.They would follow as I went up,and down in the menu,and were over the text,and not behind.One was a dotted red line.While doing that,the TV then started showing vertical lines instead of horizontal.The menu then was behind the lines.Here are a couple of pictures.This is with the replacement T-Con board.Bad T-Con board?Any help is greatly appreciated.Thank You very much!
Tyler
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File Type: jpg 2.jpg (179.9 KB, 32 views)
File Type: jpg 3.jpg (199.0 KB, 27 views)
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Old 09-13-2013, 11:38 PM   #4
capkid
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

I'm leaning towards a bad panel - possibly a tab bond issue. Budm is the tab bond guru.
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Old 09-14-2013, 12:54 AM   #5
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

This one is bad on the right side:
http://www.badcaps.net/forum/showthr...LN52A530P1FXZA

http://s807.photobucket.com/user/bud...?sort=3&page=1
Already try reseating the left ribbon cables?
__________________
Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/

TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809

Last edited by budm; 09-14-2013 at 12:57 AM..
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Old 09-14-2013, 05:00 PM   #6
70JUDGE
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

I read online if I unplug the LVDS cable,and the lines don't show on the screen,the screen is not the problem?

Did you have more then one bad tab?I would think more then one would have to be bad to cause lines on half of the screen.

Wouldn't the silicone pads hold the heat in?I see laptops have them on the video chip,but not on the CPU.Why even have it on the video chip?

Wouldn't the tabs overheat with the metal frame removed,and the TV not upright?

Does your T-Con cover have any thermal pads?Mine doesn't.Just an indent that I can't tell if it is in contact with the chip,or not.

I haven't reseated the ribbon cables that go from the T-Con to the screen.It doesn't look like there is enough room to undo them with the bezel,and metal LCD frame on.

Is the metal LCD frame one piece?How sturdy is the stand?Can I mount the TV on the stand with the bezel removed?

I see a video online of someone flexing their Samsung LCD TV,and one of the ribbon cables working it's way loose,and causing half of the screen to show vertical lines.Wouldn't flexing the screen also show a bad tab as well?

Thank You very much!
Tyler
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Old 09-14-2013, 08:44 PM   #7
budm
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

"I read online if I unplug the LVDS cable,and the lines don't show on the screen,the screen is not the problem?" Panel will no longer drive signals and voltages when you disconnect the LVDS cable so the screen just become just a piece of glass, that is why you will not see any lines on the screen, it does not the screen is OK.

"Did you have more then one bad tab?I" Two, and they are very sensitive, you have to push it at the right locations to see the changes, you are talking about 30~40 lines of contact points.

"Wouldn't the silicone pads hold the heat in?" The silicone pad is the thermal heat transfer pads, not just a silicone. You can Google thermal interface pad.

"Wouldn't the tabs overheat with the metal frame removed,and the TV not upright" There are ICs mounted on the flexible circuit board that drive the TFT on the LCD glass panel, they use the fram as the heat sink, so do not run the panel with the frame removed for more than 2~3 minutes or you damage the ICs, as you can see it can get up to 155F.

"Does your T-Con cover have any thermal pads?" I do not remember, what ever pads it has on yours, they will need to be put back on or you will fry the ICs.

"Is the metal LCD frame one piece?" each panel designs are different, some are 4-piece, some are two.

One warning about doing repair or checking for bad tab bonding is that you have to take the LCD frame and connect everything back together and mount everything back in place and run the TV with power, it is not an easy job and the panel can easily be broken.

By the way, bad TFT drive ICs can also cause the lines on the screen.
Please go here and down load bunch of info about T-CON, LCD panel ,etc. I put lots of info there.
http://www.badcaps.net/forum/showthread.php?t=25810

Last edited by budm; 09-14-2013 at 08:46 PM..
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Old 09-15-2013, 03:30 AM   #8
70JUDGE
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

Does the large main CPU chip on the T-Con get very hot?Why I ask is when I put the original T-Con back in the TV to see how the TV acted(It acted the same),I noticed the square indent in the T-Con cover isn't deep enough to have it make contact with the CPU to act as a heatsink.There is about 1/8" gap.There was no thermal pad in there when I took it apart.I bought the TV used,so it could have been removed by someone else.Wouldn't the whole screen have lines if the T-Con CPU was overheating?

Thank You very much!

Tyler
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Old 09-15-2013, 02:06 PM   #9
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Default Re: Samsung LN46A540P2F LCD TV Has Random Horizontal Lines On Left Side Of Screen

There should be thermal transfer pad there that is why there is an indentation on the metal shield.
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