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 conclude that I purchased the wrong TCON card. If you go to 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,
LJ94-02353J Sony TV Module, T-Con board, 550HHC6LV0.7,
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 conclude that I ordered the wrong board. I placed an order for the first board yesterday. Oddly enough, it cost less, $55.60 + $11.49 shipping. I have the first card boxed up to ship back Monday. Unfortunately, I will have to pay a 20% restocking fee for my mistake.