T-Con or Edgelite diode?

[PlayDoh]

So I have 2 Sony KDL-60ex645 TV's, both started having issues with the edge lights on the bottom at nearly the same time, after 5 years of use. Pretty coincidental.
One of them is now on the six blinks, edge light issue and no display. On this one, as with the other it had what looked like a dead LED along the edge.


After a couple months however this LED turned back on , and the one to the left of it went dead. Also the one that was out, was too bright. Unfortunately I didn't get a pic of it before it quit.

That made me speculate the T-con board even more. I have the TV torn down and have tested the T-con board and its readings indicate problems. This is according to a YouTube video regarding the same board testing. He mentions that when testing it, and specifically the one component, that if its faulty the issue is most often with the display. Yet I can't make sense of that with an Edge Lit TV.

His reading of a good board
Drain = 15.5v I read up to 45v then down to zero as it tries to start up 3x
Gate = 3.5v I read 4.2v again 3 times and back to zero after each attempt
Source = 0v I read 0-0.01
He does a Diode test on the Drain and Source and gets .4, and says if its 0 the board is bad. I read 375, which I assume is .375
Next a continuity test on Drain & Source which should be 0, I get 1100 Ohms

So, obviously I'm no tech and its seems also obvious the board is bad. Since Both TVs have the same issue, the chances 2 LEDs on the same edge no less would go out at the same time after 5 years is much less than both T-Con boards.

at $25 for a T-Con its an easy gamble. I'm just wondering if anyone can give me some advice, or correct a misunderstanding. Here is the video "T-Con Board RUNTK5261 Test - How to Find Faulty Component Showing Bad TV Panel"
https://youtu.be/yTnkOfwBGGE

[diif]

Re: T-Con or Edgelite diode?

That's an edge lit LED failure. T-con issues tend to affect the whole screen or a half of it.

[budwich]

Re: T-Con or Edgelite diode?

But the linked video is pretty specific in its logic. It is indicates that if you don't get the expected measurments, then the card is bad BUT... what the guy in the video keeps expressing many times, is that there is a likely reason for the tcon to go bad and that's because of an issue with the panel. Your picture looks like a panel lighting issue. You probably need to check the connection going to the edge lighting areas along with the component leds to see if its a connection issue or component failure. LED's can be replaced BUT its a pretty involved operation.

[PlayDoh]

Re: T-Con or Edgelite diode?

[PlayDoh]

Re: T-Con or Edgelite diode?

The LEDs are on a flex cable, which is just glued to a board. I can find the boards fairly cheap, and that will be a likely buy next. Yet I can't find the actual LEDs, or any that actually look like them. I'm presuming these are the LEDs, the black rectangles in the 2nd, 3rd and fourth pictures, in between the black frame and the boards.

Since the LED that originally went dark, came back for a day, and then dark again, and then a month later it came back on and the one next to it went dark, I'm finding it hard to think it is a LED. and the odds that one LED on 2 identical TVs would go out within weeks of each other, seems unlikely.

A cable / connection seems very possible, and swapping out those could be a solution.

I thought about taking the second TV apart and swapping back light components one at a time, and see which one it is by elimination.

[PlayDoh]

Re: T-Con or Edgelite diode?

I think in the Youtube video his "the boards are ruined by the panel most times", is concerning a back-lit TV, yet I guess that dosen't even make much sense. The T-con board and display panel are essentially separate components. The only thing they share is a connection to the main board. Its like saying your speakers are effecting your back lights, in my logic.

And both TVs display was and is perfect aside from the edge light. How a fault with the panel, that doesn't effect display at all, yet kills components on the T-con is hard to imagine.

[PlayDoh]

Re: T-Con or Edgelite diode?

This is from the ShopJimmy info regarding my board

"IMPORTANT: The following picture symptoms indicate a bad LCD panel, and NOT a bad T-con board:

-One side of the picture is darker than the other
-Picture has horizontal line(s)
-A dark, cloudy spot spreads across the picture

Installing a new T-con board in a panel with one of the defects above will result in damaging the new board.

IMPORTANT: Horizontal lines on the screen are virtually NEVER caused by a bad T-con board. Horizontal lines indicate a defective LCD panel (screen). "

Now lines on screen I can understand, but just how the panel could be at fault for edge lights is beyond me.

[budwich]

Re: T-Con or Edgelite diode?

I don't think you are looking at the leds. You are looking at the tab drivers which aren't replaceable. I haven't seen an edge lit panel (there are posts of some) by the leds are different.

[PlayDoh]

Re: T-Con or Edgelite diode?

I don't think you are looking at the leds. You are looking at the tab drivers which aren't replaceable. I haven't seen an edge lit panel (there are posts of some) by the leds are different.

Ok, now I got it. This is the LCD driver tabs. Looks like I have to flip the whole thing to get at the LEDs and my T-con board was a waste.

[vinceroger69]

Re: T-Con or Edgelite diode?

This video will give you a rough idea how to get too the leds
https://www.youtube.com/watch?v=Bf5T2wwtydY
The main thing is take your time and be very careful with the thin lcd panel as easily cracked/chipped etc

[SLK001]

Re: T-Con or Edgelite diode?

Like everyone else has said, those aren't your LEDs. To get to the LEDs, you have to remove the panel. Just remember that when you get to the "lifting out the panel" stage, the panel must be near vertical. The panel is too fragile to lift it out when the panel is flat (like on your work surface). Lift the panel off and stand it vertically again a vertical surface while you repair the LEDs. Use white cotton gloves so that you don't smudge the panel with skin oils. Above all else, keep the panel and the diffusers clean. There is nothing worse than having to disassemble the panel again to remove carpet fibers, hair, dust, etc.

[PlayDoh]

Re: T-Con or Edgelite diode?

Like everyone else has said, those aren't your LEDs. To get to the LEDs, you have to remove the panel. Just remember that when you get to the "lifting out the panel" stage, the panel must be near vertical. The panel is too fragile to lift it out when the panel is flat (like on your work surface). Lift the panel off and stand it vertically again a vertical surface while you repair the LEDs. Use white cotton gloves so that you don't smudge the panel with skin oils. Above all else, keep the panel and the diffusers clean. There is nothing worse than having to disassemble the panel again to remove carpet fibers, hair, dust, etc.

What I did was slide some sturdy cardboard under the panel, under the diffuser, and just slid the panel back far enough to get at the strips. Got them out and about to order replacements.

I didn't see your post till after I was done. I haven't separated the panels and my workspace is fairly clean and dust free. Its too bad they didn't think enough to make the edge lights accessible without lifting the panel.

Thank you very much for the tips and advice. I have another TV to do once I'm done with this one, so I'll use your 'proper' method on that one.

Thank you also Vince for the video. I'd never lift the panel out the way he does however, yet I'm sure 42" vs 60" makes a big difference. You'd think I was working on a Mars Rover the way I'm working. I bought a 65" replacement so I have all the time in the world to work on this one.

Merry Christmas

[vinceroger69]

Re: T-Con or Edgelite diode?

yes for small lcd panels that video is ok like you say, some people use thick paper/cardboard or even suckers too lift the larger panels like you did ive used thick lining paper in the past on a 46in set as didnt want too risk the lcd flexing.