RAINBOW color lines on LCD screen !!?? - AVS Forum
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post #1 of 15 Old 12-10-2009, 10:43 PM - Thread Starter
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My TV shows just RAINBOW color lines, wth's wrong?x Where to look problem?
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post #2 of 15 Old 12-10-2009, 11:52 PM
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A picture would be nice. Is it rainbow lines without any video information on the screen? Try going to a non-HD input and see if the lines change width when you change the aspect ratio (normal to zoom). If they move it is the video process board. If they don't it is the TCON board.

Those who think they know everything annoy those of us who do.
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post #3 of 15 Old 12-11-2009, 04:54 PM - Thread Starter
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No information and no inputs, it suppost to be start by LOGO name and then show inputs but mine ligts up and then it goes to RAINBOW vertical lines(1/16" thik ones).
It had problem before too but now i can't let it work anymore.
What's TCON board? BACK LIGHT INVERTER maybe ? It's fixable ? Maybe some caps are dead and i'll replace them(on another mainboard some of the small caps are bulging, do you think that should be problem too?).
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post #4 of 15 Old 12-12-2009, 05:06 PM - Thread Starter
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Any more recommendations ?
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post #5 of 15 Old 12-12-2009, 05:10 PM
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It's probably a loose LVDS Cable or a bad image processing board.

If its just a loose cable it should take a tech about 5 min to fix.


(The LVDS cable is what connects the LCD to the main board)
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post #6 of 15 Old 12-12-2009, 11:58 PM
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Quote:
Originally Posted by Quad5Ny View Post

It's probably a loose LVDS Cable or a bad image processing board.

If its just a loose cable it should take a tech about 5 min to fix.


(The LVDS cable is what connects the LCD to the main board)

If only it was that simple. 4 or 5 years ago LVDS connectors had some issues. They are very robust now and rarely cause problems. Without a picture I would say TCON probem.

Those who think they know everything annoy those of us who do.
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post #7 of 15 Old 12-13-2009, 10:52 AM - Thread Starter
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What's TCON problem?
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post #8 of 15 Old 12-14-2009, 03:20 AM
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Quote:
Originally Posted by GEOgamer View Post

No information and no inputs, it suppost to be start by LOGO name and then show inputs but mine ligts up and then it goes to RAINBOW vertical lines(1/16" thik ones).
It had problem before too but now i can't let it work anymore.
What's TCON board? BACK LIGHT INVERTER maybe ? It's fixable ? Maybe some caps are dead and i'll replace them(on another mainboard some of the small caps are bulging, do you think that should be problem too?).

If you've noticed bulged caps... replace them first. My bet would be AV processing board... but it is really very hard to say...especialy without any photos…

If the TV is old and you are willing to replace caps yourself.... it may be very nice learning experience... most of the PCB’s inside the LCD TV (apart from power supply and inverter boards) are multi-layer PCB... and you should know what that means before you try to replace the caps...

Otherwise, call service to fix this problem.... if the TV still holds some reasonable value...

T-CON board is timing control board (or pixel driver board). This board accepts LVDS differential signals from AV processor board, provides timing correction (generates smooth looking picture), and generates 2 main groups of high speed signals that actually "drive" the LCD panel itself: scan driver signals and data drive signals... very high degree of synchronisation is required here... and very fast signal recovery times (paired with fast LCD panel refresh capability)... so if all the “ingredients” are of high quality / high specs -> it all comes in to place nicely with 240Hz refresh… hence the price premium we have to pay for those models…

Boky
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post #9 of 15 Old 12-14-2009, 11:33 PM - Thread Starter
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Quote:
Originally Posted by Quad5Ny View Post

It's probably a loose LVDS Cable or a bad image processing board.

If its just a loose cable it should take a tech about 5 min to fix.


(The LVDS cable is what connects the LCD to the main board)

Quad you are rigt, was LVDS cable pins problem, they had bad touching(banded pins), so do you think the best soulution is to move pins litle up?
Because after pressing ribbon down TV lights up perfectly. Or put something under preasure between TV cover and metal frame ?
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post #10 of 15 Old 12-15-2009, 03:27 AM
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It's up to you, but that sounds like a temporary fix.

Would it be possible to take a picture of the the cable to show us?
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post #11 of 15 Old 12-15-2009, 04:40 AM
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Hi GEOgamer,

can we see the photos please? the cables you are referring to are connected between which two boards? can you show us the photo of a problem-connector?

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post #12 of 15 Old 12-15-2009, 04:37 PM - Thread Starter
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http://www.fixya.com/uploads/Images/C47399F.jpg
http://www.fixya.com/uploads/Images/3CFE79A.jpg
http://www.fixya.com/uploads/Images/8160173.jpg
http://www.fixya.com/uploads/Images/F49C805.jpg

On the first picture under small metal cover is 1.5-2'' wide connector with 20 or more pins, that's the problem and need to fix, another end goes to motherboard but it's good secured.
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post #13 of 15 Old 12-15-2009, 06:27 PM
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I couldn’t see any ribbon cables…. So it is probably one of the standard connectors – dual in line, two rows, 10 pins in each raw…

What you need to do is basically figure out if the problem is related to loose connection between connector plug and socket, or there is cold solder joint / cracked track just underneath the “connector socket” on the PCB… from what you posted already… you may have cracked PCB track on the board.

You could unplug and then plug back in the connector – this should break any contact resistance… if that’s the problem… if this does not fix the problem… you’ll have to remove the PCB and check for broken tracks / loose soldering between connector pins and PCB tracs…

Good luck

Boky
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post #14 of 15 Old 12-16-2009, 05:38 PM - Thread Starter
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Pins are bented so is better to try fix them up or put it under presure and so they will be flat enough ?
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post #15 of 15 Old 12-17-2009, 06:34 AM
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Quote:
Originally Posted by GEOgamer View Post

Pins are bented so is better to try fix them up or put it under presure and so they will be flat enough ?

I am trying to visualise and figure out what is going on there with that connector and bent pins. Unfortunately, I am afraid that your explanation is just not good enough and / or I am misinterpreting what you wrote..If you could take the macro shot of the bent pins in question that would be great

Boky
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