Samsung UN46B6000 image problem *with pictures*

[jermi4]

Hello,

New to the forum and first post but I have a good number of years of experience as a hobbyist repairing electronics and troubleshooting. I enjoy taking systematic approaches to troubleshooting. If you have specific recommendations and experience with this problem please let me know.

I picked up this set for free and would like to get it working again. The images below tell the story of what is going wrong with it.

When first turned on you can see finely spaced horizontal black/grey lines. The image then begins to flare across the screen vertically. Flare worsens over the next 5 minutes and then stabilizes. If you change to a new image the flare from the previous image remains but over time adapts to the new image. This occurs regardless of the image source. Black lines remain static the whole time although flare occurs over them. In the photos the beach picture is the internal image test and the smaller photo is off a USB drive.

What I've tried so far:

1. Turn off and leave off for >24 hrs --> no change.
2. Examined all electrolytic caps --> no bulging/leaking.
3. Warmed and cooled boards with hairdryer --> no change.
4. Measured power output from power board --> stable voltages and correct as listed on board.
5. Purchased replacement t-con board from ebay --> different and worse problem than with my t-con board. contacted ebay seller who refunded me and didn't want their board back . . . seemed like they were selling a bum board
6. Disassembled down to the ribbon cables attaching to the LCD panel and prodded each one while watching image --> no change.

Thoughts:

1. Still highly suspect of the t-con board but wanted people to weigh in before I pony up for another potentially DOA board from ebay.
2. Some evidence that I've seen out there that this may be a problem with the LCD. But if it is then? That sounds like a voltage or overheating issue to me although I can't find it.

Looking forward to your expertise.

[tom66]

Re: Samsung UN46B6000 image problem *with pictures*

Unfortunately, this would be a bad LCD panel.

[jermi4]

Re: Samsung UN46B6000 image problem *with pictures*

Unfortunately, this would be a bad LCD panel.

For my LCD education what about the board causes this problem? It seems so dynamic that it's hard to believe it could be the display causing it. In my mind the LCD simply converts the electrical signal in it's final processing to the image.

[tom66]

Re: Samsung UN46B6000 image problem *with pictures*

The LCD is a lot more complicated. It is an active matrix LCD so every subpixel has a TFT for controlling it. Then along the edges of the LCD glass are bonded controller ICs which seem to be often the cause of failure. So whilst the glass may not be what has failed, the chips controlling the glass, which are bonded to it, have failed.

Some people have had success removing and resoldering these bonded flex tabs, but it is a very difficult job and success rate is low.

[Dang]

Re: Samsung UN46B6000 image problem *with pictures*

These lines can be controlled some what, you need to access the service menu(user be warned) and find an option called " Sub Contrast" (plenty on how to enter the service menu on these boards), turn it down to about 75 with an adjustment of the "Sub Bright" control to about 145, exit and fiddle with your settings until you get it where it's best, it will definitely compromise the picture quality but you will have no more lines.