LN-T4069f video issue

[vbrad511]

I picked up this dead Sammy, and replaced the power board. It fires up, but the screen is acting up. It'll get flickers, slow images, and passing dark sections. The menus and subtitles show up just fine. Not sure where to look. Ideas?

[nomoresonys]

Re: LN-T4069f video issue

rolling dark sections sounds like a panel/tab bond issue, try flexing the panel a little see if anything on display changes.

[vbrad511]

Re: LN-T4069f video issue

I thought about that at first, but wouldn't the tab-bond issue affect the menu and subtitles?

[vbrad511]

Re: LN-T4069f video issue

Well, I've killed it. I pulled it apart and found the upper left tab to be the problem. I cut pieces of 3mm thermal pad and placed them accordingly, but in the process I managed to partially dislocate one of the tabs on the left side down by the bottom. Now I've got a permanent horizontal stripe that I can't get rid of. On the next set, while I part this one out, I guess.

[vbrad511]

Re: LN-T4069f video issue

Can't seem to leave this one alone. It's got a horizontal stripe, rather a series of lighter/darker stripes, about 5 inches wide that start on the left of the panel (the side where the tab pulled away), and fade as they travel to the right. I pulled it apart again today, looking for a way to reaffirm that tab back down the rest of the way, but sure fell short. Any ideas at all?

[Truncatedhose]

Re: LN-T4069f video issue

I think you shouldn't have pulled it apart as you were correct: a panel problem would have affected the OSD as well.

[tom66]

Re: LN-T4069f video issue

A picture of the fault would help a lot.

[vbrad511]

Re: LN-T4069f video issue

1st attempt at loading pics....

[vbrad511]

Re: LN-T4069f video issue

What's seen in these pics is after I place some plastic shims under and on top of the offending side tab. With the shims not there the stripe was clear-pictured, but darker than the rest of the tv.

[tom66]

Re: LN-T4069f video issue

To me... that looks like a defective LCD panel... sorry!

[vbrad511]

Re: LN-T4069f video issue

I place silicone pads on the upper tabs several days ago and the original problems basically went away. There was still a "little" odd behavior when cold, but once it warmed up (3 or 4 minutes) it was crystal-clear, for as long as the set was on. It only developed the stripe after I pulled it back apart to thicken the pad on that upper left corner, and ended up damaging the one on the vertical side. At this point I'm debating pulling the other side tabs loose and removing the plastic shims around that left tab to see what it does. I get the feeling the pic is going to fade lighter on the left side, but again, what is there to lose at this point...

[vbrad511]

Re: LN-T4069f video issue

Well, given the shape of things I figured there wasn't much to lose, so I tore into it one more time. It was the tab on the left vertical side at the bottom that'd come loose, and the makeshift shim and pressure pad did change it, but not much, and it took a fair amount of pressure to even get that much. Without that pad and shim the picture was still there, just a bit lighter than the upper 3/4 or so of the screen. There were no wires attached to the tabs so I thought MAYBE they redirected signal through the lcd, and seeing as one of them being displaced lightened the picture and didn't kill it, so why not disable the other 3 on that side, so I did. Got it back together and things look fine. I had to make a few adjustments on the settings, and I've got a very thin blue line on the out left edge, but I'm happy with it. I MAY try to reset the silicone pad on that upper left tab, or I may not..