Sony KDL-55W807C horizontal lines/rollover/ghosting

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Sony Television

Repair guides and support for televisions manufactured by Sony.

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lektroflow @lektroflow

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Sony KDL-55W807C horizontal lines/rollover/ghosting

The TV is from 2016.

A few months ago the problem started appearing more and more right after turning the TV on. Most of the time it stopped and stayed away when turning it off and on again, but now that trick doesn't work anymore.

It looks like horizontal lines/rollover/ghosting and is wavering, also in the left corner of the screen there is a bright spot on and off clearly visible on a dark screen when booting up for example:

You can see it better in the video:

I also hear electrical buzzing around the tcon board, it seems to be a few seconds louder every time the lines appear.

I already reconnected all of the ribbon cables, no change.

Could it be the tcon board or is it more something like the LCD driver or power supply?

The tcon is a T550HVN08.4 Ctrl BD 55T23-C0G, see pic:

UPDATE: pics of bufferboard:

UPDATE2: close-up of the chips on the buffer/matrixboards:

left faulty screen half board U001:

right screen half board: U001:

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@lektroflow this does not look like a common T-con board failure. Ty something like this. Unplug the power from your TV and disconnect one of the ribbon cables from the T-con board to the LCD buffer boards. Then plug your TV in and turn on your TV. You will only have 1/2 a screen but see if the anomalies are still there. Then try the other side. Disconnect power, reconnect the first ribbon cable, disconnect the other ribbon cable, reconnect power and turn your TV on. What do you get?

oldturkey03 의 5일 전2025년 3월 23일

@oldturkey03 Thanks for the input.

Disconnecting one ribbon makes the left screen half (where the bright spot in the corner is) always white but the right half looks normal without anomalies this time.

Reconnecting it again and disconnected the other makes the whole screen white stripes and anomalies.

Swapping the 2 ribbon cables makes no change.

lektroflow 의 5일 전2025년 3월 23일

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@lektroflow this does not look like a common T-con board failure. Ty something like this. Unplug the power from your TV and disconnect one of the ribbon cables from the T-con board to the LCD buffer boards. Then plug your TV in and turn on your TV. You will only have 1/2 a screen but see if the anomalies are still there. Then try the other side. Disconnect power, reconnect the first ribbon cable, disconnect the other ribbon cable, reconnect power and turn your TV on. What do you get? — oldturkey03
@oldturkey03 Thanks for the input.

Disconnecting one ribbon makes the left screen half (where the bright spot in the corner is) always white but the right half looks normal without anomalies this time.

Reconnecting it again and disconnected the other makes the whole screen white stripes and anomalies.

Swapping the 2 ribbon cables makes no change. — lektroflow

oldturkey03 @oldturkey03 평판: 812.8k 1.2k 920 2.4k · Answer 1 · 2025-03-23T10:35:57-07:00

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oldturkey03 @oldturkey03

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@lektroflow yes, the cables are different so swapping is not a good idea. This sounds like the buffer board to the side where the screen still shows lines etc. has failed. See if you can get some pictures of those boards and if they interconnect. Your TV may have two or even four of those boards. We'd have to see if we can maybe find the issue on those boards. These boards are considered part of the LCD display by the way they are connecting (special bonding procedure) and are not replaceable. Check for the bonding of each CoF (which are the "plastic" ribbon cables that connect the boards to the LCD). See if you find corrosion, tears etc. You will only have to focus on the side with the anomalies (left half :-)

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After more screws, metal panels, feet, brackets, etc takes off, I've made pictures of the bufferboard of the bad screen half :) See my edited post above.

I can't find any corrosion or burnt spots.

Pressing on the board or bonding wires (with both tcon ribbons connected) seems to make no change to the anomalies.

Maybe the chip on that board has become faulty?

lektroflow 의 4일 전2025년 3월 24일

@lektroflow can you make out any of the writing on the IC U001? I wonder if VG8-VG14 would correspond to the gamma voltages. Are you in a position where you could measure those points. If you are, use a multimeter in VDC voltage. Black on ground and red on each point starting with VG8. Also, does it have the same points on the other boards? Can you get to those to measure the voltages on that? Do the same for the VGx points on your T-con board. Let's see is the voltage is identical

oldturkey03 의 4일 전2025년 3월 24일

@oldturkey03 The U001 chip of the left (faulty screen half) buffer/matrix board is a i7824DA P520456

The other board has a different U001 chip: R28T G1564

See close-up pics in my updated post above.

I measured the voltages (both ribbons connected & TV turned on) on the boards from VG8 to VG14, first on left, then on the right, and also on tcon.

I didn't write down the tcon values because they were almost the same as the right BD voltages, a little bit higher than the left one:

[left BD] [right BD & tcon]

vg8 7.51 7.54

vg9 7.34 7.38

vg10 5.30 5.33

vg11 4.09 4.12

vg12 2.49 2.51

vg13 0.50 0.52

vg14 0.30 0.33

lektroflow 의 3일 전2025년 3월 25일

@lektroflow those voltages look good as well as consistent. No Gamma IC issue here. The two IC's are both OP amps with the same characteristic just different manufacturers. Now here comes the bad part, since we do nto yet have any schematics for the buffer boards, and we still can't totally rule it as the cause (also based on symptoms and preliminary testing it's about 90%) see if can find a good used T-con board and replace yours. That way we can be ruling the buffer board either 100%in or 100%out. After that we need to see if a Tape-off or cutting the CKV lines might fix this. I'll see if I can come up with any schematics.

oldturkey03 의 3일 전2025년 3월 25일

@oldturkey03 Can I try connecting the tcon output left to right board and vice versa?

And optionally swapping the bufferboards if I can safely remove+reconnect the CoF ribbons?

That way I could rule out the tcon and/or bufferboards.

Also what do you think about the buzzing, I think it's coming off the tcon board?

lektroflow 의 3일 전2025년 3월 25일

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