Re: Sony KD49X8000H - Sound, backlight, no picture
I believe I have found a patent that explains why blocking either of CLK3 or CLK7 will allow the display to show an image.. It looks like the signals may feed into each others node controllers, so blocking either of them essentially blocks both of them. I don't believe there is a way to only block the one that is actually having an issue.
[url]https://patents.google.com/patent/US8860650B2[/url]Re: Sony KD49X8000H - Sound, backlig...s why blocking...
MoreMagnets
Member
Last Activity: 07-10-2023, 06:55 AM
Joined: 10-21-2022
Location: New South Wales
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Re: Sony KD49X8000H - Sound, backlight, no picture
Further testing has discovered that the panel will display an image with CLK3 OR CLK7 blocked. Image is not clean with CLK3 AND CLK7 blocked.
So something that is shared between these CLK signals must be shorted.
edit: have tested the original PSU. TV doesn't respond to any input with it installed....Last edited by MoreMagnets; 10-26-2022, 07:30 AM.Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
Man I am at a loss with this thing. No shorts detected ANYWHERE. No bad caps that I could find, maybe my testing methodology is wrong? I have tested the resistance of the caps/resistors. I have also tested the capacitance of the caps, they all seem to match the board on the opposite side of the panel.
I know that blocking CLK3 brings picture back, but I do not know WHY and that bothers me to no end. I think I'm missing some critical changes that LG/Sony have made to the way the CLK signals function in these newer 4k...Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
Managed to get a close up of the pixels to demonstrate the issue I'm having when blocking CK3. In this case I have blocked CK3, CK6, and CK7.
Is it just me or does it look like half on the pixels on those lines are actually activating and then skipping the next pixel? Potentially an issue with the data lines and not the clock signals as once thought?...Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
Attached images of the front of the right side panel driver board.
Blocking VGH_ODD did not fix.
The hunt continues.......Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
Unfortunately didn't grab one. Will get a picture when I am in front of the TV again.
I think I have potentially found the reason for my issues with black lines. Did some research and found the patent for LGs Gate-In-Panel circuitry:
[url]https://patents.google.com/patent/US10026354B2/en?oq=15%2f366923[/url]
As well as this handy youtube video for the function of TCONs and what different manufacturers call different signals:
[url]https://youtu.be/izd7dhtmZjc?t=1058[/url]
...Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
No shorts or low ohms on the caps on this right side board.
Did further testing on the image with just pin 4 blocked and it looks like the bright band isn't actually present if just that one pin is out. Only when most or all of the pins are blocked. So, positive if I can figure out what is going on.
Still getting the black lines if I only block pin 4 though, tried blocking 1 other pin at a time in case it was two bad CLK circuits on the gate drivers horizontal to the panel; no dice. Could be three bad CLK...Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
I have managed to follow the CLK traces down the Gate driver board to these resistors on the end furthest from the TCON ribbon cable. No short detected on panel side of any of them and they all seem to be testing a steady 100ohms.
[U]The hunt continues![/U]Re: Sony KD49X8000H - Sound, backlight, no picture
I have managed to follow the CLK traces down the Gate driver board to these resistors on the end furthest from the TCON ribbon cable. No short detected on panel side of any of them and they all seem...Leave a comment:
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Re: Sony KD49X8000H - Sound, backlight, no picture
Uploading my random voltage testing photo.
(Note photo has both ribbons connected. Tests were actually taken with the right one removed)...Leave a comment:
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Sony KD49X8000H - Sound, backlight, no picture
Hello all!
This post will mostly just act as documentation for my undertaken troubleshooting steps for this TV. Advice will also be appreciated for things to try next
Picked up the TV in thread title from a retail returns auction, symptoms were as described. I started my troubleshooting attempts by shorting the 19V PSU rail to the 3v rail with my multimeter... Doh. Big spark, dead PSU, TV not turning on anymore. Picked up a new mainboard and PSU locally from someone here in Sydney, wasn't sure if my butterfingers had killed both and was a big drive to pick them... -
Re: Sony Bravia KD43XF7596BAEP - Android no picture
I get all the normal startup noises, yes. Will start my own thread for further troubleshooting rather than continuing to discuss in OPs.
Thanks everyone for the advice...
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Re: Sony Bravia KD43XF7596BAEP - Android no picture
Correct. I could hear the menu sounds when pushing up and down on the remote but only had backlight, no image. Tried troubleshooting steps posted in here and got same result as OP with half black, half white and then all black.
On another note is there a trick to figuring out which pins to block? I thought I had it with pin 1 but must have just been some adhesive blocking another pin temporarily. Got image back on just pin 4 but getting some pretty wicked horizontal black bars.
Tried...Leave a comment:
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Re: Sony Bravia KD43XF7596BAEP - Android no picture
Great guess. Just had a very small bit of tape on pin 1 and it must have moved. Used a bigger bit of tape over pins 1-4 and we have picture back again. What's the downside to covering up more than a single pin? Worse image quality?...Leave a comment:
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Re: Sony Bravia KD43XF7596BAEP - Android no picture
Update. Just did the tape trick, got video for about 10 minutes while I went through the android TV setup. Then all of a sudden green horizontal bands and the display goes black. Can still hear the android menu music but no picture again. So panel issue confirmed? Hopefully that wasn't the panel nuking my TCON board cause I tried to make it work...Leave a comment:
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Re: Sony Bravia KD43XF7596BAEP - Android no picture
I'm having almost the exact same issue with a Sony Android TV. Have replaced power board and mainboard so I think they can be ruled out. Left right panel ribbon behavior the exact same as you when they are removed.
I'm thinking it could be a dead TCON as well as a dead panel. Did you ever fix this?Leave a comment:
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Re: New Members - please post your introductions here
Hi All! Having problems with my Sony TV in Australia and coming for some advice
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