samsung un65nu6900f common problem, digging deeper

[itelite]

Ive done a few more of these over the years. When the problem matches that as originally posted, the resistor swap seems to work. The suitable resistor value does seem to vary though. Ive found putting a small potentiometer in the place of the resistor is great to make the fine adjustments to resistance required to get the best picture. You can turn the pot and watch the color saturation change until you get too high or too low of a resistance (causing a reboot). You can then either leave it, or measure the resistance and replace it with a SMD resistor of the same or very close value.

[nomoresonys]

Since it's not likely to be stuck, you can bookmark or save, maybe subscribe for future access but my subscribes vanished.

[nomoresonys]

This is a very informative thread and can potentially save a lot of these tvs, I think it should be a sticky so it is easy to find. Owner would probably have to do it, I don't think the mods have the mentality.

[petersor]

Quick update - still working well after 5 months . . .

[nomoresonys]

Ok, you were right about it just being a settings tweak, was my first thought as well.

[petersor]

I played with the setting on the FireTV and the TV a bit and it's now working perfectly. I think the TV is supposed to auto-detect the resolution, F/R etc. so maybe it was something on the FireTV side. Either way, problem solved.

Rich

[Diah]

satsified

Follow-up to my previous post. 10k resistor in R13246 caused a boot loop so I tried a few higher values - 27k, 33k & 47k. All allowed the TV to function properly with great picture so I left the 47k resistor installed and put it all back together. Everything works fine using the built-in streaming services, but my Amazon FireTV produces sound but no picture through either HDMI port. I'm thinking it's probably due to a setup issue that I'll investigate, although I would think it should be plug and play. I can live with onboard streaming for now.

I took a few voltage measurements on R13246 about halfway through the resistor swaps so I'll share those. Voltage at the 'top' of the resistor was consistently around 25.x V:

27k - 19.6V
33k - 18.7V
47k - 16.6V

Rich

however you are satisfied but this is not enough.. as you dismissed the frame rate Freq & resolution...

That is curious, did you try another hdmi device or another hdmi cable?

no way even if cable in high resolution.

[nomoresonys]

Follow-up to my previous post. 10k resistor in R13246 caused a boot loop so I tried a few higher values - 27k, 33k & 47k. All allowed the TV to function properly with great picture so I left the 47k resistor installed and put it all back together. Everything works fine using the built-in streaming services, but my Amazon FireTV produces sound but no picture through either HDMI port. I'm thinking it's probably due to a setup issue that I'll investigate, although I would think it should be plug and play. I can live with onboard streaming for now.

I took a few voltage measurements on R13246 about halfway through the resistor swaps so I'll share those. Voltage at the 'top' of the resistor was consistently around 25.x V:

27k - 19.6V
33k - 18.7V
47k - 16.6V

Rich

That is curious, did you try another hdmi device or another hdmi cable?

[petersor]

Follow-up to my previous post. 10k resistor in R13246 caused a boot loop so I tried a few higher values - 27k, 33k & 47k. All allowed the TV to function properly with great picture so I left the 47k resistor installed and put it all back together. Everything works fine using the built-in streaming services, but my Amazon FireTV produces sound but no picture through either HDMI port. I'm thinking it's probably due to a setup issue that I'll investigate, although I would think it should be plug and play. I can live with onboard streaming for now.

I took a few voltage measurements on R13246 about halfway through the resistor swaps so I'll share those. Voltage at the 'top' of the resistor was consistently around 25.x V:

27k - 19.6V
33k - 18.7V
47k - 16.6V

Rich

[petersor]

Some more data points as I'm working on one of these right now. I've tried 15k & 22k resistors for R13246 so far. The TV starts fine with either, but as soon as I add an HDMI Signal to either input, it stops booting. If I plug the HDMI in after it boots, the picture goes dark but the sound remains . . . I'm going to play with a few other resistor values, starting with 10k and then 4.7k to see if it will boot with HDMI connected. I'm wondering now if this is possibly and HDMI issue . . .

Rich

[papakarlo74]

Thank you to all the guys posted above!
5 cents from my side: to make a proper red color I've brute forced different values and found the best result for R13246 - 47K
10K - TV did not start

[xfox]

I just turned off Instant On option in Eng menu, now TV is working ok

[Cornito]

Hi xfox,
I've place a DC to DC step up between the 12V on the input from the mainboard to the VGL to avoid this kind of issue

[xfox]

Hello guys, so delay switch powered from USB is not working perfect, USB can randomly turn off while watching TV, I need to find some other 5v source, or 12v, have also 12v delay timer relay, any ideas where I can get 5v turn on? Also I was thinking ab 555 timer, need 1-2 sec delay, can someone suggest R and C for 1-2 sec?

[Cornito]

you right, it's not a good TV, but anyway we spent money and that shit and if we can save some time before having to buy another one it could be great, this will reduce our wastes.

I'll try to fix what can be fixed, and if there is nothing really acceptable, i'll resign to put this in trash.

Samsung should be under class action for that mess

[Storyteller12]

This is a cheap TV with a known screen defect.
Not worth all the trouble to be honest. I appreciate the dedication to trying to find a solution but sometimes things just belong in the trash. This tv being one of them.
Between the bad screens, the backlights burning out and melting diffusers.

[retrorepair2]

Didn't it die anyway? I may just let someone else have a go, seems like a lot of work for no real reward

[Cornito]

You can check pictures i've posted on # 101
https://www.badcaps.net/forum/troubl...89#post3205489

Regards

[Cornito]

So this confirm the fact that it's on the main driver that you've got the issue.
I had the same case, I cutted the VSS line on this driver, that permitted to get an image, that was not good, I needed to cut CKV lines and link them to the ground to be able to get a not so bad picture quality.

[retrorepair2]

This TV only has one LVDS cable, you can separate the sides on the filter board but it won't then turn on at all.

This is a UE70AU7100KXXU. Confirmed before doing it there was no voltage on the VGH test point on the main board and now there is but it looks like this