Samsung LH82QENELGC/EN Help needed - Static line on screen

[Kiberge]

HI guys!

I've got a Samsung LH82QENELGC/EN with a problem and need some advice and I hope this is the forum to use?
I'm from Norway so I'd like to apology in advance if my description of the fault is kind of simple or the names on the components are way off. 😊

the TV is powering up, working as normally and picture is all good, except a 1.5-inch-wide vertical line of snow/static across the screen.


This TV is a Signage Display/Public Display version and it's been used at my work for 4-5 years showing commercials 24/7. The fault occurred when there was a glitch in the main power for half a second. Just a glitch long enough to turn off/on all power in the building. When tv restarted the fault was there. Nothing else electronic as damaged in the building.
The TV was replaced with a new one, and the old one was free to grab 😊

I've opened the tv and checked for loose connections and signs of overheated or burned circuits on the circuit boards.

And I tried to swapping places on the ribbon cables between the t-con and the screen (COF's?) to see if the fault moved on the screen.

I've also tried to wiggle on the COF and move the ribbon cable between the COF and the LCD screen without anything happening.

Anyone that would like to set a diagnose? Screen, COF, T-con??

If the COF or screen are broken, I guess there's nothing to do.

But could the fault be in the t-con board? Would it be any sense testing another t-con?

Regards Knut

[Kiberge]

[Diah]

for me its not connection issue .. or COF.. its data lost. upload photos please of the main boards t-con and the LVDS, let see its just one or double

[Kiberge]

Is this what you wanted?

[Diah]

extract this archive and copy all photo on USB root. and play them on the set., let see how it will act with USB source and flat data

[Kiberge]

This is how the images looks like

[Diah]

1- you can play this test again with one ribbon discommoded a time.
2- could you remove the heat sink from MB and let see clear high resolution photo to know more about the signal... if there another CPU beside the main Soc

[Kiberge]

1- you can play this test again with one ribbon discommoded a time.

If you mean like this, there's no image showing on screen, only backlights.

[Kiberge]

2- could you remove the heat sink from MB and let see clear high resolution photo to know more about the signal... if there another CPU beside the main Soc

Heat sinks removed from both boards

[Diah]

okay... the best way to narrow the issue.. you need to run the T-CON and panel as stand alone.... it mean
1- disconnect the LVDS cable between Mainboards and T-con from T-con side
2- disconnect the socket between powerboards and mainboards BL will come on..
check the Fuse close to black sockets at t-con if it had 12V with this configuration .. if doesn't have you need to unplug the sockets and fed the fuse with 12V from PSU cold area 12 rail

[Kiberge]

Removed these two cables and I've got 12v at this fuse.

Baclight on, but screen's only black, no image.

[Diah]

sorry man.. there are no more test we can do, only i can say for me this issue lost data from this line under the SoC if its BGA or defect Soc channel... only Oscilloscope and data sheet of repair manual belong to this mainboards will help.

[Kiberge]

So next logical step would be to search for a second hand main board then?

[Diah]

So next logical step would be to search for a second hand main board then?

No at this moment i wouldn't recommend for replacement, take out the LVDS between MB and t-con and check with high resolution focused photo of the contact pins from both side

[Kiberge]

All the contact pins looks ok.

I also turned the LVDS around 180 degrees. So, I connected the end that was on the MB to the T-con and vice versa.

In my thinking, if the fault was in the LVDS or a PIN the fault should have been different, or the line should have moved on the screen because the faulty pin vas moved?