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#1 |
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![]() Hi
The issue I am trying to locate is seen in the attached Images. I.E What should be repaired. The TV got a bump / fell . Works fine - almost General Design is Standard LED TV : PSU , Main, T-con with 2 Flex cables - to 2 Panel Boards. The only issue is with the image quality. The TV Menu's Image Settings are medium/standard. nothing extreme. The General look is Solarized ? : White shadows , Darkish , and colors are too strong Most important in my opinion are the Grayscaled areas. I tried cellotaping tracks on the Flexes. No joy. I do suspect the Gamma system. I traced them to To the T-con Big Chip - marked in an image. T-con was inspected with magnifying glass - looks OK. Any suggestions ? It's a 65" TV ![]() |
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#2 |
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![]() left ribbon cable not in correctly
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#3 |
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Line Voltage: 120VAC 60Hz
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![]() Each gamma voltage should be in asending or desending order depending where you start.
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#4 |
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![]() Gamma Voltage results photo
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#5 |
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#6 |
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#7 |
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![]() I really don't think you have gamma problem. What do you get when disconnecting each side?
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#8 | |
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![]() Quote:
While the Gamma measurements look mostly fine : I assume the line starts on one board and comes back on the other : all are paired with same V basically , BUT one : the 0.447 and the fluctuating V . This fluctuating test point doesn't seem to be connected, but it strengthened the guess that I have Gamma issue ( started with image having grayscale areas) I am uploading a sequence of images for each Flex since there's this "fading" phenomena vs "Popping right up" as in normal display . They are named "Left #" and "Right #" , with description in them Thx ! 65" ![]() |
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#9 |
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![]() Seem to have problem on right side. Have you checked other voltages on t-con?
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#10 |
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![]() gate drivers from one side are not receiving a signal, i think VGH or VGL, must open screen bezel to show if present COF or COG, if COG repair not possibile maybe unless you shut off bad side
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#11 | |
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![]() Quote:
I did not check V as I am not knowledgeable in them ( I might be finding the fault without knowing that I did) , I can't find a pdf explaining this subject but I found on Youtube a new, pretty good, channel . Here's a link to one clip of the series https://youtu.be/I3dFanaLdTc I did not check V since I assume(d) they are fine : The LOGO appears OK, and I was/am under the assumption of Gamma issue. I don't have a oscilloscope for the (twisted ?) Pairs In short : what should I check and what should I see ? Thx for the help ! |
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#12 | |
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![]() Quote:
![]() I want to make certain I understand you : 1. VGL or VGH lines ( Which Flex / Side of the visible Panel ) are damaged. 2. I should find which exactly by investigating the COFs ( COF = COG ?) on the Panel ( Top or Side COF ? ) 3. Assuming I find an anomaly, I should repair the line/s or, If not possible , MASK ( cellotape) the track on the Flex from the T-con ? OK. Since Dskall and you converge on "other Voltages", I will take VGL VGH measurements : on T-con and further down the line, upload, and let you tell me what you think. The plan is to measure every test point which is marked by VGH/VGH. It will take some time, so I would appreciate if you would "follow" this thread. Thanks ! Last edited by Ancient1; 11-24-2021 at 03:20 AM.. |
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#13 |
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![]() Watching from the front and with the screen right the fault is in left side so the right in your pictures, cof are those chips external from the screen, in newer lcd they can be within the glass and their name are COG, so if you find COF you can gently scrape testpoints on film and test in both sides (i am talking about vertical sides tabs) to find which testpoint is vgl and vgh in good side then in bad side you can test if one of those are interrupted so you can reconstruct it by wire..
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#14 | |
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![]() Quote:
What I understand from the rest is : check the "good side" COF ( Chip On Flex) and compare to the "Bad Side" : they should be mirrored. You ( me) may see correct VGL ( for example ) on the boards while the line is damaged in the Panel ?? I will. I've seen , mostly ppl in India, do that. For now, I decided to measure ALL Test Points on the Panel Boards. Takes some preparation With regard to the boards : is one the IN board and the other Out board ? since I have Gamma test point clusters in both boards |
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#15 |
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![]() Watching from the front and with the screen RIGHT the fault is in left side.
For the restdo one thing a time, remove bezel from the screen and we see if there are side tabs.. |
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#16 | |
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![]() Quote:
There are Side Tabs , I repaired a couple of LEDs , than replaced all. long story I wanted to be sure : I check the Side Tabs COF for V , not Continuity or such, right ? Also, are the Left and Right Tabs a mirror image ? does the line come from , say, (Panel Board) Left side , through the Row , to the Right and back to the other Panel Board ? Thanks !! |
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#17 | |
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![]() Quote:
If you have VGH, VGL test points on tcon it's better to check continuity, do it first to the good side so you can find the correct testpoint, there are on the net collections of testpoints, search if you want the code impressed to the tab near the word datasheet. The VGH lines are not running trough the row but are split in 2 in the tcon, 1 for left, 1 for right. Left / right tabs are mirrored. |
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#18 | |
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![]() Quote:
OK, I understand better what to do ! Thx ! Last edited by Ancient1; 11-25-2021 at 12:02 PM.. |
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#19 |
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![]() VGH/VGL testpoints are on one side but signals are split in two, if you use continuity test of multimeter you find the signals on both connectors..
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#20 |
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![]() Ok
Right side board - Right as in the full photo - All Test Points Measured : Due to its Length : I have 6 images , consecutive from Left (mid TV) to Right , i.e as you would see the board * few points have cycling mV : 0 to ~350 usually |
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