Samsung UN65KU6300FXZA no picture

[eagle00799]

Good day everyone! I'm looking for some help/advice/direction with this Samsung UN65KU6300FXZA with no picture. When powered on the backlights come on for a couple of seconds then dim down for a couple of seconds then it powers off, powers back on and repeats the same process over and over again and there is never any logo or anything just a bluish screen and the only way to shut it off is to unplug it. when I disconnect the plug connecting the power supply to the main board the backlights come on and stay on, when I disconnect the ribbons on the main board one at a time it doesn't change the screen at all, I've always gotten a white half screen on the side that was disconnected with other tv's I've worked on. Is this a bad panel? I know there have been EEprom issues with these tv's!?!? Advice?
Here is the layout of the tv.

[neilc6]

Re: Samsung UN65KU6300FXZA no picture

That model doesnt have a tcon board so you cant do the half screen test. I have seen bad panels (cracked) which will cause no video and unstable backlight. Like the guy in this post, you can try disconnecting the interconnect cable between panel boards to see if the video will come up and isolate which section of the panel is bad and also look for shorted caps on these boards. https://www.badcaps.net/forum/showthread.php?t=87562

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Thanks for the reply neilc6, I pulled the innerconnect cable first on one side with no change at all, then the other side with no change at all. any other ideas?

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

a pic of the blue screen

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

tried to give a link to a video but disregard

[budwich]

Re: Samsung UN65KU6300FXZA no picture

a pic of the blue screen

is that a small horizontal line in the bottom left hand corner of the panel or a reflection? IF its a line, you have a panel issue.

[budm]

Re: Samsung UN65KU6300FXZA no picture

You need to test the Tab bonding/Panel boards next.
You have to get the speakers out off the ways then remove the two metal shields to see the boards.
BTW, no body ever spray windows cleaner on the screen, correct?

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Budm, I did take the metal covers off and removed the ribbon that connects the 2 boards, first on the left side then reinstalled the ribbon and then I did the same on the right side and it made no difference on the screen on either side. as far as the line, when powered on I get the horizontal lines on the bottom 3rd of the screen but they go away. it's almost like it's trying to display the wifi banner that goes across the bottom of a normal screen but it just can't do it and the lines go away!?!?

[budm]

Re: Samsung UN65KU6300FXZA no picture

I need to see the pictures of those boards.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

like this banner on the lower screen is what I was referring to

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

I will try to get some better pics, and I just picked up this tv so I wouldn't know if they used any window cleaner but I wouldn't be surprised if they did.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

pics of tab bonding/panel boards

[neilc6]

Re: Samsung UN65KU6300FXZA no picture

Tougher to troubleshoot possible tcon problems but with no tcon board. I salvaged a newer Samsung RU series and it was down to just a single combined power supply/main board and no screws.

The one I referred in post 2 had a L shape crack on the edge and turned on with no video and an unstable backlight. I ripped the tab bond off at that end and got it to display video so confirmed panel problems can cause no video.

[budm]

Re: Samsung UN65KU6300FXZA no picture

Looking at the pictures of the bonding boards, I can see some Voltage test points, I.E VCC_3.3V, AVDD, Etc. that you may be able to check.
See example pictures attached.
The T-con circuits are on the main board in this on.
If you can look at the main board around the LVDS connectors may be you can locate the AVDD test point some where on the main board.Picture of the main board is not clear enough to see Voltage test points.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

neilc6 I have a 60" Vizio that I put new backlights in but while I had the screen set aside my cat decided to chew on one of the side ribbons, when I put it together that side of the screen was white and it had horizontal lines across the screen parallel with the damaged ribbon. I thought it was a goner but Budm suggested to peel the ribbons off on the side that was damaged and it was like rising from the dead, it worked. I was so excited that when I put it all back together I didn't make sure the screen was sitting in it grooves when I screwed the front bezel on and it cracked the screen on the edge but it still worked so I put a strip of black tape along the edge to cover the crack and my wife still hasn't noticed lol.
So does this Samsung have side ribbons also?

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Budm I will check on the test points tomorrow as it's after 8pm here and gotta get up early tomorrow morning.

[budwich]

Re: Samsung UN65KU6300FXZA no picture

you are lucky though.... you can do some more testing before going after any side tabs.
you posted a picture of the bottom edge / tcon boards. There are "U" cabling interconnecting the sections of the edge board. Although, I can't tell... but it is likely that there are two edge boards per half side of panel. IF so, the "U" cables can be unclamped / disconnected. This will isolate the "1/4" outside portion of the panel along with any side stuff without doing any permanent damage (ie. like tab removal).
With all cabling connected on the set (ie. power, main, tcon), disconnect the "U" cable (with power disconnected / off).... power up and see if anything changes. Try the same test with the other side. IF you are lucky, you may see a display of some sort.

[budm]

Re: Samsung UN65KU6300FXZA no picture

BTW, the picture in your post #10 is what is shown on your screen? I thought you get nothing on the screen at all at this point.

[budwich]

Re: Samsung UN65KU6300FXZA no picture

I think that is a picture from another screen... you can see he has a tv in the back of the set that he is working on. He was just trying to indicate what the screen "should" look like if it displayed properly as opposed to that "very little line" in the bottom left corner.

[budm]

Re: Samsung UN65KU6300FXZA no picture

But that picture is from the thread here POST #2: https://www.badcaps.net/forum/showthread.php?t=87562 of difference OP.