Interesting problem with KDL-55XBR8

[jehill]

My KDL55XBR8 is 5.5 years old. Every 6th horizontal line is dark on the left side of the screen and progressively returns to normal as you follow the line to the right. I Googled the problem and found one other person with the same symptoms. The corrective action suggested was to replace the panel. However, it dosen't appear to be a panel issue. Panel issues are usually the result of poor connections or failed drivers. This would result is red, green, blue or black lines the entire width (or height) of the screen. I talked to a tech at http://www.tristatemodule.com and he recommended replacing the TCON board. The TCON board comes pre-installed on a panel if you can afford one. The Sony part number for the TCON board is 185722312 and they want $177.73 for it. Tri-State doesn't have a cross-reference to the Sony Part number. Instead, they have two manufacturer's part numbers listed and you must look at your part to determine which to order. Their boards only cost about $75.

I removed the back and found that the CB1 board must be removed in order to get to the TCON board. I stripped the head of one of the screws holding a heat sink in place that must be removed because it was in so tight. I had to drill it out. Fun, right!

Here are a few photos:

Space shuttle launch illustrating how every 6th line is dark on the left and progressively returns to normal moving from left to right.



Close-up of left side of screen.



Close-up of right side of screen.



View of TV with rear cover removed. Notice the two heat sinks at the top middle. The top one is attached to the TCON board and the bottom one is attached to the CB1 board.



Close-up of the TCON and CB1 boards. Notice that the top lip of the CB1 shield overlaps the TCON shield. For that reason, the CB1 board shield must be removed first. Also, notice what looks like foil attached to the top of the TCON shield. It must be removed VERY carefully.

[jehill]

The photo below shows the CB1 board shield removed. I then started removing the TCON board shield by removing the five screws that hold it in place. Once again, I had to drill out one of the screws. Then I discovered that I still couldn't remove the shield. That led me to removing the foil tape attached to the top of the shield. I very carefully worked it loose from one side to the other with my fingers. You can see where it was attached in the photo. Then I discovered that the reason I can't remove the shield is that the four connectors at the top connected to the panel and the two connectors at the bottom connected to the CB1 card must be removed. That brought me to a halt, because I was unsure how to remove the connectors. However, I was lucky and discovered that the board part number is behind the lower right tab of the shield. With an LED flashlight I was able to read the first 6 characters, 550HHC, which is all that was needed for me to determine which of the two TCON boards I need from www.tristatemodule.com. It cost me $73.45 + $11.49 shipping to order the part. Hopefully, customer service will be able to help me figure out how to remove the connectors. I put the parts removed back together so that the wife and I can watch TV until the new TCON board arrives.

[jehill]

The photo below shows the TCON board cover at the top and the CB1 board below it. If you look closely, you will see that the ribbon cables from the panel to the top of the TCON board and the two cables from the CB1 board to the bottom of the TCON board have been disconnected. It was apparent how to remove these cables after inspecting the new TCON board. Each ribbon cable connector has a black horizontal locking bar across it. You just pull the locking bar towards you with a finger nail and lift the ribbon cable up and out of the connector. The two connectors at the bottom of the TCON board pull out and swing down to get them out of the way. Thus, there is no need to remove the CB1 board, only it's shield.



The photo below shows what comes off in your hands when you remove the five screws that attach the TCON shield to the chassis. This was a big surprise. The TCON board drops out of the shield for easy replacement.



After swapping out the old TCON card for the new one and re-installing the removed parts, I plugged in the set and turned it on. To my dismay, the power relay clicked once, the Sony logo lit, the power relay clicked again and the Sony logo dimmed. There never was a picture. I re-installed the original TCON board and the set works as it did before. I took photos of the old and new boards while I had them both out to see what part numbers appeared.

Photo of the original board. The part number is on the small white tag at the lower left. It begins with S2353H.



Photo of the replacement board. The part number on it begins with S2353J.



Based on the information above, I concluded that I purchased the wrong TCON card. If you go to http://www.tristatemodule.com and search for kdl55xbr8, you will find the following two TCON cards listed:

LJ94-02353H Sony TV Module, T-Con board, 550HH6LV0.7,
KDL-55XBR8

Board #: 550HH6LV0.7

Part #: LJ94-02353H


LJ94-02353J Sony TV Module, T-Con board, 550HHC6LV0.7,
KDL-55XBR8

Board #: 550HHC6LV0.7

Part #: LJ94-02353J


I ordered the replacement TCON board based on the first seven characters of the board number that I could see on the original board without removing it from the shield, 550HHC6. I concluded that I needed the second card, since the first seven characters of the board number for the first board are 550HH6L, not 550HHC6. The original and replacement boards do have the same board number, 550HHC6LV0.7; however, they have different part numbers. The part number on the original board contains 2350H as does the Tri-State part number for the first board. Thus, I concluded that I ordered the wrong board. I placed an order for the first board. Oddly enough, it cost less, $55.60 + $11.49 shipping. I shipped the first board back. Unfortunately, I will have to pay a 20% restocking fee for my mistake.

[jehill]

I received the new TCON board and installed it. The board works, but does not correct the issue. I have a CB1 board on order now, part number A1557695A. Let's keep our fingers crossed that it corrects the issue.

[jehill]

I received the replacement CB1 board today and installed it. Unfortunately, it didn't correct the subject problem (Every 6th horizontal line is dark on the left side of the screen and progressively returns to normal as you follow the line to the right). I talked to the Tri-State tech again. He is convinced that the panel is bad. Apparently, the problem is caused by a board physically inside the panel assembly. This is bad news. It looks like I will have to live with the problem until I decide to replace my KDL55XBR8.

It turns out that I miss-answered a question that the tech asked me before he suggested that I replace the TCON board. He asked if the on screen menu was effected and I incorrectly answered no, suggesting that the problem didn't appear when the on screen menu was up. The tech wanted to conduct some tests on my set to confirm that the panel is bad, but I wasn't home. I will call him again next week and run through the tests.

[jehill]

The tests indicate that the panel is bad.

[jehill]

There is new hope. Extreme_Boky's post in the following thread explains how to clean the contacts on the ribbon cables from the TCON board to the panel:
Sony KDL-46XBR4 Panel Problem
I'll try that next.

Here's a picture of the cables to refresh your memory:

[jehill]

I'm done! I buttoned up my KDL55XBR8 after cleaning the contacts on the four ribbon cables from the panel to the TCON board and discovering that it made absolutely no difference!

Cleaning the contacts was pretty easy to do. First, I removed the end of each ribbon cable connected to the panel. Then, I removed the end connected to the TCON board. I used the technique described the link in my last post. Here are some photos:

Photo of two of the four ribbon cable sockets on the panel. They are the ones in focus at the top. They are identical to the sockets on the TCON board that are out-of-focus.



Photo of the contact side of one of the four ribbon cables. I cleaned the contacts on each end using the hard eraser on the end of a pencil. I moved the pencil eraser parallel to the conductors off each end. I rotated the pencil as I moved along. The eraser did get dirty, but the contacts looked clean to me before I started.

[jehill]

New development, every 3rd line is dark

I now believe that the real problem is the FBU board. Unfortunately, it doesn't appear to be available anywhere. Getting it rebuilt may be the only option. Here's why I believe that the FBU board is the source of the issue:

Earlier, before my first post here, I suspected that the FBU board creates a 1080 line raster and superimposes the video on it. Now, I am convinced of it.

Here are the latest photos:

Photo 1: Now the lines go entirely across the screen. Also, note the vertical lines directly above the Hallmark logo. This is definitely a video problem. The white level isn't returned to normal as fast as it should after the Hallmark logo is scanned onto the screen.



Photo 2: Left side of the screen



Photo 3: Right side of the screen

[jehill]

Every 6th line is dark again

Are you ready for this? This AM (9/23/14) I turned on the TV and every 6th line is dark again, but this time the lines are nearly normal on the left and get darker to the right!