Samsung un65nu6900 bonds get extremely hot

[itelite]

This is a new one for me. all of the flat flex bonds from the panel to panel pcb get extremely hot in about 20 seconds from power up. at which point the screen goes from displaying a perfectly normal image to a bunch of colored lines. They are getting hot on the PCB side of the connection.

Like burn your finger hot.

I dont know what to make of it, i could see if it was just one maybe, but every one if them starts cooking.


any ideas?

::EDIT:: On further observation it is the ICs inside the bond cable getting hot, not the connections themselves.

[Diah]

Re: Samsung un65nu6900 bonds get extremely hot

this is really strange if they all got hot.. like the clock Freg goes to them higher than they designed for..
start first upload photo on the T-CON and the riboon which goes to panel..
disconnect one side of ribbon and see if the picture remain clear on the half screen displayed
be ready to turn it off if they goes hot

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

i can upload a photo, but not a ton to see. no separate icon on this one. disconnecting either side shuts the whole panel down. these are not identical left and right side pcbs either.

yeah it is very odd. i too was thinking some kind of a runaway situation. measuring random voltages on the pcb, nothing really changes from clear to lines. i have no reference for what things should be, but nothing looked terribly strange to me.

[Diah]

Re: Samsung un65nu6900 bonds get extremely hot

i can upload a photo, but not a ton to see. no separate icon on this one. disconnecting either side shuts the whole panel down. these are not identical left and right side pcbs either..

this cant be.. no TV on market like as you talking on panel pcbs unless if the set OLED QLED

over clocking could happened when the signal feed was external.. always best test local signal or USB media such JPEG other wise the panel scrap

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

photo of boards.
https://itelite.org/wp-content/uploads/IMG_1111.jpg

As soon as i loosen the ribbon hinge clip it shows colored lines for a fraction of a second, and then blackness.

as far as source, this is a smart tv, and this happens before even selecting a source. Right in the main GUI screen.

[Diah]

Re: Samsung un65nu6900 bonds get extremely hot

this is panel with integrated T-CON .. search after shorted ceramic caps on the board

[dick_barton]

Re: Samsung un65nu6900 bonds get extremely hot

What is the VCC voltage on the integrated Tcon?

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

vcc as tested from a labeled test point on the panel pcb is a steady 3.3v.

No shorted caps anywhere on the panel pcb

ive noticed that on occasion it will display only a black screen, ICs will generate no heat. startup sound will happen. if i unplug it for a few minutes, then i can get display for a some seconds before the ics cook and the colors on the screen.

Are we talking about integrated tcon on the main board, or the panel pcb? panel pcb looks to be many passives an eeprom and a few other small things. nothing at all close what i would see on a traditional tcon board.

[Diah]

Re: Samsung un65nu6900 bonds get extremely hot

the LVDS on the left side cover the first 4 pin with thin type then place it in. turn on.. hope it wil block the over clocking and remain on with out cooking

[budm]

Re: Samsung un65nu6900 bonds get extremely hot

Can we see the pictures of the whole integrated T-CON in section?
The integrated T-con is fed by switched 12V from the main board which is then step down to 3.3V, 1.8V, etc, and also get boosted for VGH, AVAA (for running COF). You can also test points for VGH, VGL, ect.
I would start checking the resistance of the caps on the T-CON.
COF temperature can get up to 150 F or more: https://www.badcaps.net/forum/showth...ht=tab+bonding

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

yes. will take a bunch of photos when i get over there today.

I would say its getting way hotter than 150. Cannot keep finger on it for more than a second or 2.

the customer agreed to throw a main board at it. so thats ordered. Im not super hopeful, but it was cheap enough.

[Unspun01]

Re: Samsung un65nu6900 bonds get extremely hot

Any update on this repair? I have same TV (UN65NU6900F) which turns on and off as normal, but only black screen with no video (backlights on, or flicker on/off from time to time).

I have not opened the TV yet, but curious of your findings. Please reply.

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

If memory serves this was a panel issue and we ended up just scraping it. You problem may not be the same. The primary symptom on this one was the tab bond driver ICs getting extremely hot. As they heated the image on the screen got progressively worse.

[nomoresonys]

Re: Samsung un65nu6900 bonds get extremely hot

Check the screen for an image with a flashlight, hit menu if needed see if there's an image.

[henryvrensburg]

Re: Samsung un65nu6900 bonds get extremely hot

Good day guys

I got two of these Samsung UN65NU6900 TV's from a restaurant group. One, when switched on come on with only black screen, backlights on, sound on, responds to remote, no image with flashlight. If I take of either of the two tabs going to the panel, in both cases the right side comes on white. The other TV when switched on, showed perfect picture, but with vertical bar about 6 inches wide on left side. It eventually worsened to same as above.

Is this a panel problem, or can someone give some advise.

Thanks for reading this.

Herewith photos of boards inside this TV.

[itelite]

Re: Samsung un65nu6900 bonds get extremely hot

I think there is a general panel defect on this model. Only my opinion, but i know in my case we did replace the main board and it made no difference.

[nomoresonys]

Re: Samsung un65nu6900 bonds get extremely hot

Probably the same issue Bud had with the bad tab bonds, maybe break it down to the tabs and apply light pressure on the tab/s see if picture clears up, I would try it first on the one with a picture, sometimes it's just the top left tab that's bad/loose.

[nomoresonys]

Re: Samsung un65nu6900 bonds get extremely hot

Video there: https://www.youtube.com/watch?v=purk_SyiT44

[budwich]

Re: Samsung un65nu6900 bonds get extremely hot

Good day guys

I got two of these Samsung UN65NU6900 TV's from a restaurant group. One, when switched on come on with only black screen, backlights on, sound on, responds to remote, no image with flashlight. If I take of either of the two tabs going to the panel, in both cases the right side comes on white. The other TV when switched on, showed perfect picture, but with vertical bar about 6 inches wide on left side. It eventually worsened to same as above.

Is this a panel problem, or can someone give some advise.

Thanks for reading this.

Herewith photos of boards inside this TV.

I may be reading it wrong... not sure I understand "If I take off either of the two cables going to the panel, in both cases the right side comes on white".

Can you please explain, for just one set, exact what happen with each cable disconnect. It is important to get the details right so that you can focus on where the problem might lie and save the panel. A "clean white" screen on the side that is disconnected is some what "normal". The other side (connected) should show something assuming there is something to show (ie. menu or input). Pictures of the result may be worth a 1000 words... :-)

[henryvrensburg]

Re: Samsung un65nu6900 bonds get extremely hot

If I remove the left tab going from the Mainboard to the Panel, the right half of the screen comes up white, and if I remove the right side tab, the right side of the screen comes on white too. That is what's weird about these TV's.

Also, I did replace the mainboard on one TV, but with same result.

Will add a photo shortly.