Sony XBR-65X750D Horizontal lines bottom of screen

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello again, you said something that I needs more explaining for me. " Only 1 side need to work for a perfect picture." So are the lines generated on the TV because there is a fault on both sides of the buffer boards? Sorry, I'm a novice.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Thanks, I found that resisters R100 - R107 are 100 ohms and R11 - R15 are 300 ohms. I measured the resistors on both sides of the TV (buffer boards) and like you said, they were the same. The one next to the burned out one measured 103 ohms so I think they are still functional. With the on resister missing I noticed that there were more horizontal lines and they were extending half way up the screen now. I am guessing if I can successfully solder a 100 ohm resister in the burnt out spot, that I can at least reduce the lines to the bottom 6" again. I found a digital microscope at a store a little while back and tried it here, see attached photos.

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hi howardc64, The picture showing "another Flex Cable" is only a shadow from an extra light source to get a clear picture of the burnt "resistors". They are so small it is hard to get a good picture of them. I even took some pictures through a magnifying glass to try and get better pictures. I haven't checked the resistance of the "resistors" yet but if they're zero ohms, wouldn't that just be a fuse? These fuse/resistors are so small that I'm not sure how I am going to be able to replace them.
Howard, I really appreciate your help with this, thank you.

Yes, tiny and magnifying eye wear + microsoldering (or really thin tip) soldering iron necessary.

Thanks for confirmation the image below the flex was just shadow.

Start by checking the duplicate set of CLK1-8 on the buffer board on the other side of the TV for resistance (for reference). Driver signals goes up both side of the TV. Controls signals for which row to display. Only 1 side need to work for a perfect picture.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hi howardc64, The picture showing "another Flex Cable" is only a shadow from an extra light source to get a clear picture of the burnt "resistors". They are so small it is hard to get a good picture of them. I even took some pictures through a magnifying glass to try and get better pictures. I haven't checked the resistance of the "resistors" yet but if they're zero ohms, wouldn't that just be a fuse? These fuse/resistors are so small that I'm not sure how I am going to be able to replace them.
Howard, I really appreciate your help with this, thank you.

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Label shows CLK1-8 with 5 being burnt the most. I believe these are the gate driver lines. Resistors might be 0 ohm (check others)

You might have damage/short in the COF (although the pic doesn't seem to show any damage).



Inspect COF (Chip On Flex) closely There is a bunch of logic in there and many lines run between buffer board and the panel. Sometime there are shorts on COF and will show some damage marks (compare with other COFs for appearance) I fixed one with COF damages. Pics here

https://www.badcaps.net/forum/showpo...72&postcount=7

Other people have posted worse looking burnt COF pics but I can't find any at the moment.

Pic also shows another flex cable below the flex COF is on (red arrow in my edit of your pic) I've never seen that before. Would be interesting to see if any damage in there if you can lift up the buffer boards and see.

You should have an identical bank of CLK1-8 resistors all the way on the other end of TV. Check those, take a pic, and measure resistance across each CLK1-8 resistor. We can use these as reference to compared with the ones around the burn mark

If you haven't already, look through my Samsung panel signal summary earlier to understand the general background on gate drivers.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello howardc64, Well, I think we found the problem. While I was using the strips to mask the ribbon cables from the T-con board, I smelled a burning component smell. When I finished with the testing, the TV appeared unchanged from before. When I completed the disassembly to uncover the buffer boards I found 1 or 2 burned resistors on the buffer board. I took some pictures attached below and then tried to clean with a q-tip which resulted in the worst burnt resister crumbling and falling away. It must have still had some value because after checking the TV again, the picture is worse with more lines. I don't think the burnt resistors are the problem but rather a victim of another failed component somewhere else. Any suggestions? Thanks

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hi howardc64, I did start with 1/2" strips but no difference so I cut them down hoping for better results. I will try to get the pictures you asked for to you by noon tomorrow. Thanks again for the help.

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Actually one value of exposing the buffer boards is to see any signal labels.

Take picture of buffer boards. Especially around the outer most COF (Chip on Flex, its those gold color flex that is bonded between buffer boards and the panel glass. Be careful with these are they are fragile)

Also take picture around the 2 t-con connectors (CN2 and CN1?)

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello howardc64, I tried the paper strip 1/8" test with the T-Con ribbon cable per your example and the best results I could get was about the same as it was without any paper masking. See picture. Will probably have to uncover the metal shielding and try to test components on the buffer board?

I think unfortunately kind of blind on this one not knowing what signals are from t-con to buffer boards.

I think no need to expose the buffer boards at this time. I was hoping blocking off gate driver signals on one side of the panel would clear up your picture. These signals are at the t-con connector but we unfortunately don't know where they are.

Can you take a clear picture of both tcon connectors and the board traces that connects to them? power rails and column signals are fairly easy to see and we can probably avoid those. I think your gate driver signals are towards either end of CN2. Maybe we should use something wider like 1/4-3/8" to start testing near both ends on both t-con to panel connectors.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello howardc64, I tried the paper strip 1/8" test with the T-Con ribbon cable per your example and the best results I could get was about the same as it was without any paper masking. See picture. Will probably have to uncover the metal shielding and try to test components on the buffer board?

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

I just noticed that when you click on the thumbnails, the picture reverses. The correct orientation is when you enlarge or click on the thumbnails. Strange.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Thank you both for the suggestions, I will try it. howardc64, your reference to orientation of the TV got me to thinking that I didn't do a very good job of expressing that myself so just to confirm, these new pictures are facing the TV and I flipped them so it is showing the picture like you would normally view it. First picture is (as you face the TV) with the Right hand T-con ribbon cable disconnected (still facing the TV) and the second of course is the Left disconnected. I am not sure I made that clear so these new pictures hopefully will clear up any doubt.
Thanks

[Storyteller12]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Howardc64 is right on with my thinking on post 11. Seems to be panel related issue

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Thanks howardc64. I was remarking to my wife what the odds were that I would be getting help from someone in western Washington. I have tried previously to do the "scotch tape" repair without any luck but I will try it again as I could have missed it. From what I have seen, it is usually contacts 2 - 9 that have the fault but like you said, no pin outs to know where to apply the tape.
Like you I have my birth year in my handle so, I have you by 20 years (depending on how you look at it) Regards, Gil

Yeah, I started with scotch tape but thin cut paper was much easier than faster if don't know pinout. I usually start with 1/2" wide and just try various locations. If get closer, than narrow with 1/4" wide and keep on finding fewest pins. Just insert the paper in the connector, slide the flex over the top and lock the connector. Do this with power off of course.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Thanks howardc64. I was remarking to my wife what the odds were that I would be getting help from someone in western Washington. I have tried previously to do the "scotch tape" repair without any luck but I will try it again as I could have missed it. From what I have seen, it is usually contacts 2 - 9 that have the fault but like you said, no pin outs to know where to apply the tape.
Like you I have my birth year in my handle so, I have you by 20 years (depending on how you look at it) Regards, Gil

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

From your test in post #9, failure is likely on left most of the 4 buffer boards on the panel (looking from back of TV right side up)

You can try using paper/masking tape blocking method to see if can make the lines go away. Red arrow is the connector to this buffer board but requires more disassembly (speaker, stand mount, metal protection strip) or just at the green arrow where you are connecting/disconnecting the flex on the t-con.



I use thin sheet of paper cut outs with varying widths and gradually narrow down.

https://www.badcaps.net/forum/attach...1&d=1681884737

Here is your service manual. Unfortunately, no t-con to LCD connector pin out to show the signals so have to try randomly.



c64 is last name letter + birth year so not Commodore haha. I'm 45min away in Sammamish WA so PM me and perhaps can walk you through what to do on the phone.

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello howardc64 (did you Start out with a Commodore 64?)
Wow, lot of information to sort through. I am attaching some pictures of my circuit boards and layout if that might help. It will take some time to explore your suggestions (I appreciate it and thank you for your help)

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Hello Storyteller12 I tried disconnecting the left and right ribbon cables from the T-con board. When disconnected R ribbon cable, no picture (no lines) reconnected R ribbon cable and disconnect L Ribbon cable, Picture (with lines) please see pictures below. 1. R ribbon disconnected. 2. L ribbon disconnected.

[howardc64]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

Maybe problem with circuit to panel gate drivers on one side. Here is an explanation of a late model Samsung LCD panel (mostly common to most late model LCD panels)

https://www.badcaps.net/forum/showpo...44&postcount=5

Also SONY doesn't make LCD panels so they use someone elses. Should post pictures of your boards but here it is

https://www.ebay.com/itm/22478260459...Bk9SR_r50-WSYg
https://www.ebay.com/itm/12439440670...Bk9SR_r50-WSYg

Since you replaced the t-con and lines persist, failure maybe on the thin edge boards attached to bottom of the panel. Requires descent multimeter skills to probe around those boards. There are no schematics. Problems can be

• Short/failure on the board
• Short on the COF
• Short in the panel

Gate driver circuit is duplicated on both side of the panel. Useful to compare readings on one side against the other. Diagnosed an LG panel via masking method followed by comparison (read post 5-8, 18)

https://www.badcaps.net/forum/showthread.php?t=116761

[ggil44]

Re: Sony XBR-65X750D Horizontal lines bottom of screen

OK, Thanks, I will give it a try and let you know.