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Discussion Starter · #1 ·
OK, here we go. I have a Sony kdl52xbr4... when its working, it looks great. Recently it started blacking out, sound is still there but after a couple of minutes, it starts to flicker and display goes out. No lines, ghosts, or pink screen ... it just goes black BUT I can see backlight still working. Display just goes off and on intermittently and like I said... when its "on" it looks great. I ran a self test on it and the only error I get is an 01 on the T_CON line. Iv'e been doing alot of reading, trying to find someone with the same issues but everyone that has "simular" issues seems to have additional problems as well. I looks like it may be the FB1 board or the UB1 board. I have had both boards out, cleaned all connections, looked for any obvious defects and used freeze spray thinking it may be a thermal issue... no go. Anybody have any experience with this problem B4 I start throwing money at this problem??
 

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If the problem is Tcon related, I don't think either the FB or UB will solve the problem. Sony just extended the warranty on the 46" xbr 4/5 for Tcon tab bond problems. It's possible you could get them to fix it under that program, although it's not a 46". Call them and see what they say. Worth a shot. Good luck.


Schlick
 

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Spark,


I received your PM but I thought I would respond here since it may help others. The courtesy repair on the LCD panel only applies to the 46XBR4 and XBR5 models so I don’t think that route is an option right now.


This chassis uses the UB1 board to double the frame rate for the 120HZ TCON that this panel has. The problem you are describing is difficult for me to assist you with for 2 reasons: 1. It is an intermittent problem. 2. I am not there to experience it.


What do you mean when you say you ran a “self test”? Did you enter the self-diagnostics feature, or did you enter the service mode and look at the line-specific diagnostics data? If you entered the self diagnostics page a TCON error should have the number “5” to the left side. The number of times the error was detected should appear on the right side. Unfortunately, this chassis has a habit of not keeping a running count of failure events so the “1” that you saw may be as far as it could count.


I will assume that you correctly identified a TCON error based on what you saw. Now here is where it gets real interesting. A TCON error means that the Back-end microprocessor on the FB1 board has lost communication with the TCON. If this communications line is interrupted, the television should shut down and the standby LED should blink in groups of 5. You make no mention of this happening.


In your particular model, the UB1 board is located in between the path of the FB1 and TCON boards. The data communications from the FB1 to the TCON simply passes through the UB1 board. This leads me to believe there might be an intermittent connection going on at the LVDS cables. There is one LVDS cable connecting the FB1 board to the UB1 board and 2 LVDS connectors between the UB1 and TCON board. I say connectors because they are a swing-down type with no cable wiring.


Can the TCON be causing this? It could but this particular mode sends information data back to the FB1 board from the TCON to give the backlight control circuits the ability to dim the lamps during dark video scenes. The backlights usually fail to turn on when this TCON fails and I am going to have to trust your observation that they remain on when the symptom occurs.


You don’t mention how often this problem occurs. If it is on a regular basis, I would recommend the following steps. This model has boards that are heavily shielded so it might be difficult to access some parts. I am not familiar with your technical skills so you may want to pass this on to a technician who is familiar with this unit.


Unplug and re-seat the LVDS connectors coming out of the FB1 board and entering the UB1 board. This is all you need to do. There is not much else you can do with these connectors. Do the same for both sets of connectors between the UB1 and TCON board. If the problem goes away for a while (or disappears altogether) you have a problem with the LVDS lines.

The other option is to take a shot at replacing the UB1 board. It may have a problem that interrupting the data line between the TCON and FB1. Unfortunately, the TCON is not available as a separate component for this model and the entire LCD panel must be replaced.


Good luck with this information. I hope it helps to resolve the issue. This is a beautiful television and I can understand why you want to get it working properly again.
 

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Discussion Starter · #4 ·
Thanks for the replies. The self test error was detected on line 5 with a count of 1. My problem occurs soon after power up and the backlight does indeed stay on during display failure. The set does not shut down, in fact the audio continues to perform just fine. I am very comfortable working on delicate electronics and have indeed had all 3 boards out for inspection... T-con, UB1 as well as the FB1 boards. Of course there is very little to can do to repair these boards so any inspection done on these would really be only to look for obvious thermal isssues. As you suggest, maybe I should start with cable replacements and I think I may just replace the UB1 board as well. I have tried to locate all possible bad parts... The only one I am hitting a wall on is the T-con board. This is too bad because it is a replaceable item. Does anyone out there have a T-con board for sale for a Sony KDL52XBR4 ????? By the way I should mention that the FB1 heart beat is still active throughout the whole process. Thank You and Any other suggestions will be greatly appreciated.
 

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This gives me a better idea of what is going on. The unit is supposed to shut down with a 5-blink error if the TCON fails to communicate with the BE Micro so the TCON error you found may have been a one-time event. Your observance of the heartbeat LED is interesting. You must have some technical information on this chassis. Based on what you are saying, you have a significant period of time during which the picture is not present. If so, here is a trick you can try. You will, obviously, need to have the rear cover off.


While the no-video symptom is occurring, carefully unplug the LVDS connector at the input to the UB1 board. Push it in and pull it out of the socket while observing the screen. If you see ANY flashes or lines on the screen the TCON is OK. This works for most TCON boards and I have used it successfully on this model. It might bring your hopes up that I have seen the UB1 board cause more “no video” failures than the TCON. Let me know how this works out.
 

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Discussion Starter · #6 ·
Hi Display Veteran,

I tried the trick you suggested and I did get the flickering you described. In fact, IF I left the connector off for more than 5 seconds, the set shut down and I got a flashing red LED on the front panel. It was flashing in groups of 5. I unplugged the set, waited a couple for minutes while it reset, plugged it back in and then I could repeat the whole process over again. I cleaned and rechecked all connectors for solid seating, treated the UB1 board to a non-conductive , non-residue freeze spray and it made no difference. Looks like its time for another UB1 board. Please let me know what you think.

Thanks
 

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You have isolated your problem to the UB1 board. Much cheaper than a panel, eh?
 

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Discussion Starter · #8 ·
Display Veteran,

I really appreciate your time and expertise!!! I had an idea that is was the UB1 board BUT it was your suggestions that allowed me to zero in. I have found a board and am waiting for it to arrive. I will let you know the final outcome. once again,

Thanks!!
 

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Great! Send me a PM on the progress. This thread may sink into the deep hole.
 

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I had problems with my XBR4 as well. It started as horizontal bands from the right side of the screen flickering from the right to center with a darkened picture. The left side of the picture was fine. As time progressed, the picture wouldn't appear for a time on startup and the flickering lasted 15 - 20 minutes.


I was in the last 2 weeks of an extended warranty. Sony replaced the panel ($1,100CAD).
 

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Quote:
Originally Posted by grover432 /forum/post/18342333


I had problems with my XBR4 as well. It started as horizontal bands from the right side of the screen flickering from the right to center with a darkened picture. The left side of the picture was fine. As time progressed, the picture wouldn't appear for a time on startup and the flickering lasted 15 - 20 minutes.


I was in the last 2 weeks of an extended warranty. Sony replaced the panel ($1,100CAD).

That symptom is definitely a panel related issue.
 

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Hi I also have a problem with the T-Con board or at least that is what I read somewhere. When I start the TV it displays 4 horizontal strips and they have a ghost image towards the left side of the screen, after 15 or 20 minutes the lines disappear and everything looks perfect, so I read somewhere that this might be related to the T-Con board and I opened the TV but I do not know the location of the board, could someone please help me locate it? Here is the picture of my TV:
 
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