Sony Bravia KDL-46XBR4 Strange vertical colors

[x_orange90_x]

So I've had this TV for quite a few years and already done the tab bond shim hack. It worked great for a couple years then the TCON went screwy and I replaced it. Worked great for a couple more years then it started having either dim/dark ghosting on the left side, or strange vertical colored lines across the screen. Leaving it to warm up for about an hour would result in a perfect picture if it was just ghosting. When it would display the colored lines, and I'd leave it on for an hour (still with colored lines), generally turning it off and back on at that point it would work perfectly.

I ordered a new TCON because I believed that was causing the colored lines. I put it in today and immediately had the ghosting for about 20 minutes, and I chocked it up to the tab bonds, but the screen went normal and I left it on for about an hour. After that I turned it off for about 20 minutes and turned it back on and it was once again filled with colored lines.

When it displays the colored lines they do change and move with image source. I don't believe this in itself is a panel issue, but I do believe the ghosting is, which I can deal with until I'm ready to dig deep down again to the tab bond causing it.

So my question is, what is causing the colored lines despite two different TCONS? As I said, I can sometimes turn the TV off and back on and they're gone. I have attached pictures of this anomaly.

[budm]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

Dark cloud and horizon lines are Panel issue.
You need to monitor the Voltage test points (I.E. VGH, VGL, AVDD, etc) on the T-CON board.

[x_orange90_x]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

Dark cloud and horizon lines are Panel issue.
You need to monitor the Voltage test points (I.E. VGH, VGL, AVDD, etc) on the T-CON board.

Yea the horizontal shadowing and ghosting are definitely the panel. As for the colored lines and testing the TCON, do you suspect it's something from the main board or in between? I thought for sure it was the TCON so that's why I replaced it.

What is that small board connected to the TCON?

[budm]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

You have FRC (Frame Rate Conversion, so TV can do 120HZ refresh rate) board between Main board and the T-CON board.

[x_orange90_x]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

Any hunch on whats causing the vertical colored lines? Seems to be temperature related, at least from what I've seen.

[budwich]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

your likely problem are issues with the connections associated with the top corner of the panel.... shimming isn't necessarily a permanent fix (ie. the compromised tab is still compromised). Further, which tabs are you referring to with "shimming tabs hack".... IF those "hacks" are associated the end tabs at the "top" (I assume this set has tabs at the top as opposed to the bottom), then those tabs are associated with signals going thru the panel to the side tabs which then impacts both horizontal and verticals.

Depending on the "hack", potentially removing the side tabs will get you an "almost perfect" picture (ie. equivalent of removing the side tabs that other sets / DIY'ers have done)

[x_orange90_x]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

your likely problem are issues with the connections associated with the top corner of the panel.... shimming isn't necessarily a permanent fix (ie. the compromised tab is still compromised). Further, which tabs are you referring to with "shimming tabs hack".... IF those "hacks" are associated the end tabs at the "top" (I assume this set has tabs at the top as opposed to the bottom), then those tabs are associated with signals going thru the panel to the side tabs which then impacts both horizontal and verticals.

Depending on the "hack", potentially removing the side tabs will get you an "almost perfect" picture (ie. equivalent of removing the side tabs that other sets / DIY'ers have done)

The hack I'm referring to is exactly as you described. Remove the LCD frame and find the bad tab at the top. Place a thin rubber strip (shim) across the tab and squeeze the frame back on over it.

I understand how the tabs work and why they fail on these TVs. I do recall reading about other TVs where people cut the side tabs, but I don't know why THAT works.

As for my colored lines, if that were related to the tabs, then why would simply turning the TV off and back on sometimes make them all go away? It quite literally looks like the northern lights dancing across the screen, absolutely no discernable image.

[nomoresonys]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

Looks like you need to get back to the tabs, did you shim all of them? Might be another has lost contact or the same one maybe, sometimes lightly tapping on bezel will change the picture which is another indication of possible bad tab bonding.

[budwich]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

disconnect the tcon cable on the side with shim (ie. tcon to panel). what is the result? Half good image? no image? As far as why turning the tv on and off sometimes works.... well, that is for "now", eventually it will do nothing to improve things. You can try the "on off" test with the front bezel removed. Does it improve the situation or get worse?
Based on my "experience", the issue is with connections going thru the panel corner which seem to get "stressed" in some form such that the signals are compromised. Turning on and off may change that somewhat as "capacitance response" might be different at various stages..... just a guess. Just as you found out about the "shim hack", you likely read that this type of problem appears to be common for this type of sony / model.

The test of the "cable disconnection" will tell you more about where the fault lies and you can go from there.

Still further, if you are "skilled" at working at very "fine wiring" and tracing things, you may be able to track / trace some voltages going from the top edge board, thru to the panel / corner and then along to the first tab on that side. You may find a fault with the connection. It is likely a loss (reduced?) of voltage to the side connections that is likely the problem. In addition, the "shim" may be "stressing" the tab area to "correct" the problem but it could also be doing some form of stress on the panel corner itself (ie. "transitive").

As suggested, I think you will find some "relationship" between the bezel being on and off has some longer term impact such that the set will operate more frequently better with the bezel off.... again, my experience.

[Davi.p]

Re: Sony Bravia KDL-46XBR4 Strange vertical colors

Hi, i like this set, it appears beautyful tecnologically of quality design and features, the board connected to tcon that i cant see is probably an FRC, for multiplying frame rate, unfortunately the set seems to.have many reliability technical problems, i have studied much time this type of defect, on my Samsung LE40A756 that i have posted here a thread and especially on the YouTube Eevblog's video about "Samsung tv dumpster diving" and... after destroing my tv's screen with an unuseful side tab stripping, i am come to the conclusion and i'm convinced of that, that the most possible culprit is the CPU and its soldering... so my advice is to try a reflow or reballing and if it lasts some days to boost the heat sinking capabilities of it. Bye...