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Old 12-05-2017, 10:40 AM   #21
london-freddie
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Default Re: LG 43UF640V half picture

ok will try that ie wash it, thanks
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Old 12-06-2017, 06:42 AM   #22
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Default Re: LG 43UF640V half picture

ok got another tcon board (used), just fitted it and picture is good, great, NO after about 5 mins picture suddenly went back to same half picture perfect and half picture shaded, this time with a green tint to the faulty side
could this be the tcon warming up and breaking down, mainboard ? or screen panel ??
I am stumped on this now
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Old 12-06-2017, 08:29 AM   #23
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Default Re: LG 43UF640V half picture

i wonder if the the chip on the panel ribbon cables is shorting that side of the tcon out?.
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Old 12-06-2017, 08:36 AM   #24
london-freddie
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Default Re: LG 43UF640V half picture

hi vinceroger69 are you referring to a chip on the led panel driver board, did look at that yesterday but did not find any shorts on it, maybe I need to look at it again
Just took tcon back out reseated ribbons and lvds cable tv came on better picture but not perfect then picture reverted back to green shaded after a few minutes
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Old 12-06-2017, 08:37 AM   #25
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Default Re: LG 43UF640V half picture

there is no chip on the panel ribbon cables
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Old 12-06-2017, 08:56 AM   #26
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Default Re: LG 43UF640V half picture

thinking but may be thinking rubbish, is it possible to send the picture from this tv to another good working tv using say a hdmi cable.
I am thinking if the second tv shows the same half picture then the fault must be in the mainboard not the tcon or panel
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Old 12-06-2017, 11:22 AM   #27
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Default Re: LG 43UF640V half picture

Quote:
Originally Posted by london-freddie View Post
there is no chip on the panel ribbon cables
There is embedded small rectangular IC on each brown flexible cable between the Tab bonding board and the LCD glass panel.
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Old 12-06-2017, 11:38 AM   #28
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Default Re: LG 43UF640V half picture

Quote:
Originally Posted by budm View Post
There is embedded small rectangular IC on each brown flexible cable between the Tab bonding board and the LCD glass panel.
In your opinion budm could a faulty cof cause this issue, as i was only guessing as not sure.
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Old 12-06-2017, 12:34 PM   #29
london-freddie
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Default Re: LG 43UF640V half picture

will check for these ic's but will be next week now before I will get chance to look, however from what I can remember there are no ic's on those ribbons, looking at my pics of the ribbons can not see any ic's, can you ?
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Old 12-06-2017, 12:53 PM   #30
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Default Re: LG 43UF640V half picture

post 4 there usually on those ribbon cables
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Old 12-07-2017, 10:52 AM   #31
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Default Re: LG 43UF640V half picture

"can i connect left side ribbon from the tcon to the right side of the screen to see if right side of screen then works as it should?"
NEVER DO THAT!

Chip on ribbons are on the back side... i think is not possible that mainboard can generate a faulty image only at half, this is an issue from tcon-panel, watch on the long panel's boards if there are any chip, usually buffer chips, then try to freeze them when tv ON, with a piece of food from the freezer covered with a cloth to absorb drops.. see if anything changes, don't think but try... you can do some other tests.. on the panel's ffc arrive some color signals, examples R0,1,2,3,4,5-G0,1,2,3,4,5-B0,1,2,3,4,5 they're all the bits for a pixel, if image has a green tint lets imagine that Blue bit 0 makes an unwanted connection to Green bit 5 (most significant byte) then you will have about all pixels with an high green tint, so lets imagine an image without any blue, so try to hook a pc via VGA and with a paint program show an image with all but blue colours, i'm not sure but the bit leak is possible from R5 to G0 so show an image without Red component, if it shows well there's a short somewhere, maybe some dirt on panel's boards due to washing of the screen etc... if doesn't make change there's probably a stuck Green bit always high, maybe due to faulty extern COF or a discrete like a resistor on the panel's pcb faulty... You have to check them for short/open or different tensions from other nears..

Last edited by Davi.p; 12-07-2017 at 11:22 AM..
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