One vertical green line on my AQUOS LC-70LE740E TV

[Bagel]

 :scared:This is the board on this TV:

[Rasz]

changing boards with this defect is waste of money, Its bonding, in the glass itself, or driver on the ribbon.

[james_s]

The fact that it appears to be a dotted line made me think it was at least possible though not likely a problem somewhere else. I agree that it's probably something bonded to the panel, it's too bad you can't just saw the end off and make a nice 4:3 display.

[wraper]

Changing any boards is a complete waste of money. The fault is in LCD panel itself.

The fact that it appears to be a dotted line made me think it was at least possible though not likely a problem somewhere else. I agree that it's probably something bonded to the panel, it's too bad you can't just saw the end off and make a nice 4:3 display.

I don't get the reasoning behind your argument. A line means that a whole column is not working, and it's driven by IC in the panel. Also why do you mention it's dotted? Of course it is since it's a column of green subpixels.

[Bagel]

Here is what I plan on doing now:


I will apply heat (270-370°c) for 1-2s on the "1st" COF. If it does not work I will move on to the "2nd".

On each I will start in the middle and move outwards.

[Rasz]

I will apply heat

so exactly what I told you NOT to do, excellent!   
Pressing with a finger (after discharging yourself by touching something grounded) or for example credit card is all you need to detect if thats where the fault lies. Burning stuff up with zero practice of prior knowledge is how you destroy electronics.

btw this flex is also bonded to glass on the other end, fault might be there (unless its bonded internally between layers of the glass)

[Bagel]

I will apply heat

so exactly what I told you NOT to do, excellent!   
Pressing with a finger (after discharging yourself by touching something grounded) or for example credit card is all you need to detect if thats where the fault lies.

I'm sorry I forgot to mention that this approach did not work for me. What I am planning to do is risky, yes, however, I don't have any other idea by now and at this point I think it is worth a shot.

Appling pressure to the COF next to the green line did not work. Appling pressure the COF next to the other one did not work as well.

[Bagel]

According to what I have researched the POC ribbon can take 230°c long time exposure and 400°c short time exposure. So the heat will most likey be an issue for the surrounding components before it damages the ribbon itself. I will get some ribbons from an old and broken monitor so I can practice a bit.

[Bagel]

Ready for practice!

[Bagel]

Since I wasnt able to find my modern soldering station I have used this old timey heavy duty one:



Here I have three ribbons. The one at the bottom I have played around with quite a bit to get the feel for it. The middle I have applied 1-2s light touch in the middle as well as 2 points to the left and 2 points to the right. The top one is untouched. The deformation of the flex is due to me taping them onto epoxy:



Here I did apply 20s in the middle:



Here another 20s on the some COF:



Superficially they seem to be quite resilient. When I'll do this on the TV I will stick to 1-2s and a light touch. I will have a metronome running at 240bpm to ensure the timing is right.

[wraper]

 

[Bagel]

[Bagel]

The iron did not get hot enougg did it? 

[james_s]

If applying pressure doesn't work then applying heat is not going to work. Heat is a way of re-bonding a connection that has come loose, if pressing on it doesn't change anything then it is not loose.

[Bagel]

I now have tried with this one (no station directly into the powersocket) for 20s in the middel (5min heatup time):

[Bagel]

If applying pressure doesn't work then applying heat is not going to work. Heat is a way of re-bonding a connection that has come loose, if pressing on it doesn't change anything then it is not loose.

User "mon2" has recommended I open a thread in this forum:

https://www.badcaps.net/forum/showthread.php?t=101091&page=2

There a user claiming to have 13 years of LCD repairing experience believes that heat might still be a possible solution.

[Bagel]

Started with 230°C 1-2s on different points of the COF on the left and right flex next to the green line, went to 260°C, to 300°C, eventually to 370°C. The TV survived just fine the line however remained.

By playing around with the connection seen below, I can get a hole in the line. Disconnecting completly will turn the whole section white. Dont know if that is a useful clue. If there is nothing more to be done I will get rid of the TV.

[Bagel]

I hope I can gift the TV to someone local. On local listings people are asking quite some money for TVs that are more damaged than mine. Is there still any value in a TV like this?