Samsung UN70NU6070F power cycle.

[Neednos]

http://imgur.com/gallery/iqa5KiY

Samsung UN70NU6070F

Picked this tv up off marketplace for 50 Canadian coins.

Old owners say it got darker and one day just died. If you plug it in it will power cycle non stop. I opened the tv up and if you unplug mb from power supply backlight will turn on and stay on. As soon as you plug in mb it will power cycle again.

Next thing I tried was unplugging the long flat cable from bottom of tv. Doing this and waiting to plug back in will make it so that I can get a picture and sound.

Next thing I tried was unplugging this long cable again and leaving unplugged. I was able to play audio with no picture.

When it powers on it looks great, no weird lines or anything. If I can get it to stay on what a steal lol.

What should I look for? Bad tcon board? Bad power supply? Bad mb? I'm more lost than ever

[Neednos]

Re: Samsung 70 inch power cycle.

I can't seem to edit the title but if mod can add UN70NU6070F that would be great. I didn't see it in the rules until right now

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Unplug the cable on the power supply to the main board and see if the backlights stay on when the tv is plugged in like that.

If it does unplug tv and reconnect cable.
This time undo the lvds cable going to the panel 1 at a time. And then both.
Report results if the tv is still rebooting or stays on.

Note the tv will show nothing when both lvds cables unplugged so watch the led light or the optical on the main board to see if it restarts.

A lot of these NU series tv sets have bad leds. Usually it doesn’t cause the tv to reset though.

If you have the Samsung logo visible when first powered on I would say the tcon is good.
Could be panel fault or main board at that point

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Unplug the cable on the power supply to the main board and see if the backlights stay on when the tv is plugged in like that.

If it does unplug tv and reconnect cable.
This time undo the lvds cable going to the panel 1 at a time. And then both.
Report results if the tv is still rebooting or stays on.

Note the tv will show nothing when both lvds cables unplugged so watch the led light or the optical on the main board to see if it restarts.

A lot of these NU series tv sets have bad leds. Usually it doesn't cause the tv to reset though.

If you have the Samsung logo visible when first powered on I would say the tcon is good.
Could be panel fault or main board at that point

If I unplug main board from power supply back lights stay on.

If I unplug one or both of the lvds cables tv will boot and stay on

If I plug the lvds cable back in while it's on tv will work perfectly. Until you turn it off or repower it. Then it will start power cycling if you try and turn it on again. I plugged in a Chromecast and was able to play an hour of video before I tried the power cycle.

When on panel looks perfect.

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Here's a pic of the screen on. Hard to get a good pic with the display facedown.

[mlemon]

Re: Samsung 70 inch power cycle.

I can't seem to edit the title but if mod can add UN70NU6070F that would be great. I didn't see it in the rules until right now

Same here for my post, After posting it I wanted to edit the Title but was not able able and at some point I managed to but still shows the original title!

[Neednos]

Re: Samsung UN70NU6070F power cycle.

So close!

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Ok. That seems to narrow it down to the panel then. You can check the lcd board that the lvds cable connect to for bad smd capacitors.

If nothing is shorted then only thing I can think is the panel is bad. Last resort is the tape method. Try taping off some pins and see if that works. YouTube it if your not sure to get an idea

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Also it’s not good to plug the lvds cables in while tv is powered on. You can esitlybahort something if the pins don’t line up perfect

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Also it's not good to plug the lvds cables in while tv is powered on. You can esitlybahort something if the pins don't line up perfect

I will stop doing that then! I'll start looking at the bottom boards tonight for any bad caps. When you say it could be the screen is this something I am able to look at?

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Unfortunately you cannot see anything with the screen. Just have to try taping off a few pins at a time and see. It’s a tedious trial and error kind of thing.

It’s kinda odd it worked fine after plugging in the cables when the tv is powered on. Usually if there is a short it would not work. It’s must bypass a check after startup or something.

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Ya after its plugged back in it seems to work fine. So I should look for the pins labeled something like CLK cover them and trail and error uncover them one by one? I see on other videos they unplug one side of display and theyll get a half picture. For me it's nothing when I unplug either side and again when either side is plugged back in I get a full picture again.

Unfortunately you cannot see anything with the screen. Just have to try taping off a few pins at a time and see. It's a tedious trial and error kind of thing.

It's kinda odd it worked fine after plugging in the cables when the tv is powered on. Usually if there is a short it would not work. It's must bypass a check after startup or something.

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Yes that’s pretty much how you go about it for the tape. I forgot this tv doesn’t have a separate tcon. It’s built into the main board I believe.

Not positive but that may be why you don’t see anything on half the screen with just one side plugged of the lvds plugged in.

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Maybe someone else with more expertise on these types of boards could chime in and assist.

Unfortunately that’s all the knowledge I have to help without having the tv in front of me to test.

[Neednos]

Re: Samsung UN70NU6070F power cycle.

This is extremely helpful. I'll try tonight and report back!

Maybe someone else with more expertise on these types of boards could chime in and assist.

Unfortunately that's all the knowledge I have to help without having the tv in front of me to test.

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Ok. I think I got the answer for you. Came across this today. I was right on about the tape method if it’s the name problem.

It’s the top lvds on the main board. If you pull it up and the pins are facing you, cover pin 15-24 or 25 starting from the left with tape. Black electrical is best but scotch works.

Plug it back in and should work if it’s the same problem.

Let me know if it works for you. If so enjoy your new TV.

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Wow is it ever hard to get tape in Ontario ATM. Damn lockdown. Now to deal with the problem of counting these pins. So small. I've attached a pic to make sure we are on the same page.

So you think this is a mb issue? I had actually ordered a new board that shows up in about a week, if I switch it out we should be good? I want to try the tape too as I want to be able to say I got this working without tossing new parts at it

Ok. I think I got the answer for you. Came across this today. I was right on about the tape method if it's the name problem.

It's the top lvds on the main board. If you pull it up and the pins are facing you, cover pin 15-24 or 25 starting from the left with tape. Black electrical is best but scotch works.

Plug it back in and should work if it's the same problem.

Let me know if it works for you. If so enjoy your new TV.

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Yes that’s the lvds cable. Unfortunately I believe it’s the panel not the main board. The panel is shorted on the inside somewhere

[Neednos]

Re: Samsung UN70NU6070F power cycle.

Didn't mean to post the same thing twice..wanted to ask if this is repeated the same way on the other cable? If I might have to try this on both sides?

What do these pins do? Are these the clock pins I was reading about

[Storyteller12]

Re: Samsung UN70NU6070F power cycle.

Just the 1 cable. Not both
And yes, your just blocking the signal with the tape