Problems with a Sony KDL-46Z4100. 3 Wide vertical bars of discoloration - AVS Forum
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Old 11-16-2011, 07:03 AM - Thread Starter
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So Someone gave me this TV because this happened to it. I wanted to see if It was a somewhat easy fix or if the TV was junk. I read a bunch of threads on here about the ribbons and the TCON board. I didn't see anywhere that actually talked a bout these wide bars like this.



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Old 11-16-2011, 02:27 PM
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I have a similar problem with my LG 55LD520



It is only a problem on the right half of the tv. This just started happening yesterday and seems to get worse the longer the tv is on. Anyone know what I am looking at here to fix this?
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Old 11-16-2011, 05:09 PM
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If you go thru the pics at the link below, the problem you both show looks similar to their screens for defective TAB.

http://www.lcdparts.net/howto/symptom.aspx
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Old 11-18-2011, 05:51 PM - Thread Starter
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So what is a defective TAB? Also I took the TV apart to try and see the part # on the TCON board and also clean and reset the ribbon connectors from the TCON board to the skinny boards up top. Now the backlight comes on with the power, but no image. The backlight still dims depending on light.. Is there anything where the case has to be on for the image to appear? It sure doesn't look like it, but I don't know..
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Old 11-19-2011, 03:24 AM
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Don't know what skinny boards up top mean.... photo would be nice.

Check the photos i attached; you'll need to completely release the clip that locks the ribbon cable in its socket. 2 red arrows point to where you should LIFT the clip 90 deg upwards. 2 blue arrow point to properly inserted (properly seated) ribbon cable.

Second photo has one red arrow that points to the ribbon cable "prongs" that should lock in to corresponding dents in the socket BEFORE you lock the long, black plastic clip.

If you still have the same problem after you've re-seted the cables (both ends: one is between AV processing board and T-CON, the other end is between T-CON and LCD panel) -> it is most likely a TAB issue, check the third photo that points to defective TAB's....

Re-seting the cables will break contact resistance that is common cause of the problems, in particular with such a small contact area / high contacts' density + bare copper contacts that WILL oxidise with time.

Hope this helps, good luck

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Old 11-21-2011, 05:16 PM - Thread Starter
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So I have tried many times to reset the cable. No luck.. In playing with them I can get the tv to show stripes sometimes and other times nothing but white screen.. Here are some pictures of it..

These are the cables..


The top boards I was talking about..


The stripes..






You can see how they change when I move the cables.

This is also what it does on the right side when I turn it on now.. I takes a couple of seconds and then goes away.. It slowly fades to the right..

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Old 11-23-2011, 02:14 AM
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1. Check the photo I attached; the red arrow points to TAB's where the ribbon cable (that goes to the LCD panel glass substrate) could have lost conductivity with the "top board"
2. The worrying thing is the fact that you do not have the picture content on the LCD panel... this usually means an issue in AV processing …. usually BEFORE T-CON board....

Bad TAB's means new LCD panel. Check my original post, the 3rd photo that shows how to restore conductivity by using foam "bumpons" - this is only a temporary measure with intermittent results/success.

Good luck,
Boky
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Old 11-23-2011, 06:47 AM - Thread Starter
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I can actually play with the two ribbons and sometimes can make out the input info in the top right hand corner. So the image is still getting through and as you can see from the first image it used to be there until I took it apart. So playing with the two ribbon cables I can make it change the picture, but never get back to the original. Putting slight pressure on the TAB cables does not change anything. I have tried them all individually while the tv is on.. Is it possible I messed up the two ribbon cables? I have tried to reset them 50 times and no luck.. Would turning the TV on without it being completely put back together cause any problems? Like the screws that would ground each board aren't there when you turn it on? Anything like that?
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Old 11-23-2011, 12:34 PM
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Turning the TV on without ribbon cables being in place will not cause any damage

Ribbon cables do have proper orientation, check the second photo in my original post - you'll notice two white arrows imprinted on the ribbon cables...

It is possible to check conductivity for each ribbon cable link; from the T-CON board through to after the TAB's... you'll need multimeter and pointy probes (and a lot of patients...)

I think it would be good to get the brand new T-CON board at this stage. You messed a lot with the TV, so it would be good to have a good starting point - to take T-CON failure out of the equation, and then focus only on ribbon cables.

As always, getting the Service Manual will help a lot – to make sure all voltages and signals at test-points are correct, but this will also require a CRO…

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Old 12-28-2011, 09:14 AM
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Hi everybody. My TV had similar issues as those shown on the pictures posted by streissel. In my case the problem appeared only when the TV was cold, after several minutes of being ON (about 20 min) the problem then disappeared. I found the root case in one of the two top flat ribbon cables connected to the to the T-con Board. When Inspected them with a magnifier I found one cable with the plastic literally "melted" in one of the corners apparently causing a short circuit between two adjacent wires (please see the attached picture). I proceed to cut it shortening the cable length by about 1mm to eliminate the "damaged" area and it worked fine for about 1 year. Now the problem is starting to appears again and I am suspecting about a similar issue is happening with the ribbon cables. Does anyone know the part number, name or where can I order these ribbon cables? Please help!
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Sony Bravia Z Series Kdl 46z4100 B 46 Inch 1080p 120hz Lcd Hdtv Black , Sony Bravia Z Series Kdl 46z4100 S 46 Inch 1080p 120hz Lcd Hdtv Silver
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