Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

[265chemic]

Hi All,

I have a Samsung LA46A950 that intermittently was displaying issues with evenly spaced vertical green lines only on dark / black areas - this has progressed to more often and blue lines sometimes, as well as a little image distortion.

My initial suspicion was the T-CON board, which I took out and cleaned but the issue persists. A heat gun on all of the control boards makes no noticeable change. Ive also reseated the T-CON to panel ribbons (4 of them) and moving them while the panel is on doesn't seem to change the issue.

Below are some photos of the issue - notice the lines appearing in various places over the black - this makes me suspect an electronics issue vs. a panel issue - happy to hear any opinions on if I should try a new T-CON board, try to investigate panel ribbons further, or something else!





T-CON board following cleaning:


Thankyou!!

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

i would do a reflow on the tcon main ic with heatsink.. don't do it with hot air, do it on an aluminium tablet on a little kichen stove putting before flux under the chip, warm it until the chip does "the move"

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Thanks for the reply David! So you don't think this is likely to be a panel issue?

I've never done a reflow (at least in no capacity more than just baking a board in an oven for some time) so a little daunting. Do you have any detailed guides you might be able to recommend?

I believe I may have located a compatible t-con board for ~$50 also, so that could be an option if necessary.

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

don't take the spare tcon, it could be faulty, save yours, take a 20x15cm aluminium tablet 4-5mm thick, put it on a stove, remove heatsink with the help of hot air, put grease flux around chip, then warm it with air to flow under, put tcon on the tablet, turn on flame at minimum, wait many minutes until flux begin to smoke, so wait a bit then with fine pliers try to move a mm an angle of chip, if it moves and return back by itself then wait 5 sec then turn off flame and let it cool down. Now test it and if ok wash it..

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Thanks again Davi!! I will see if I can find some aluminum plate and get some flux grease and give it a go.

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Hi Davi / All,

Unfortunately no good news - I tried a reflow but now the t-con board makes a high pitched noise from the main IC and the TV won't turn on ( fast flashing red led after backlight , as if the board isn't plugged in ).

I did modify the procedure from what you suggested in a couple of ways though, I first tested the process on an old GPU with a aluminium block 80x50x5mm I got the IC to move and cooled off okay. I used a thermocouple to monitor temperature up to a little over 200deg C.

For the t-con, I did it right on the glass of the hotplate as it seemed more stable. I also couldn't get the heatsink off the IC so left it in place - it seemed too much force was needed. When reflowing I was also heating from the top side with a heat gun.. maybe I overheated the IC momentarily.

Do you have any feedback? I have ordered the replacement board.

Thanks again for your replies

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Two errors, one sure, the heatsink is too heavy to left it in place, second when you reflow on top with air you run the risk of destructive popcorn effect.. don't repeag it again if the chip is not very flat.

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Thanks, I didn't consider the weight; I guess that might flatten solder out too much, maybe causing bridging.

What is the 'destructive popcorn effect'?

I don't suppose at this stage it is worth trying again?

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

The fried eggs is done.. end titles..

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

A lesson for the future, that is for sure.

I just hope that hasn't caused issues upstream/downstream, and that the new t-con, once it arrives, resolves all issues. It is said to have been tested and is out of a unit with a cracked panel.

Do you think there is likely to now be other issues outside of the t-con?

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

i think no

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Glad to hear that! I will update once it arrives.

[265chemic]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Good news - replacement t-con turned up and has fixed the problem, so for anyone else that has a similar issue that was what resolved it.

If you try a solder reflow try to do a better job than I did!

Thanks again Davi for your advice!!

[Davi.p]

Re: Samsung LA46A950 aka. LN46A950 - intermittent vertical green lines / distortions

Happy to hear it..