samsung un65nu6900f common problem, digging deeper

[nomoresonys]

Try the tape method.

[xfox]

Got same TV (UN70NU6900FXZA) but fix did not work for me, tried different resistors, tried direct wire, with one ribbon disconnected tv does not recycle power, with ribbon plugged in 2-3 sec after power on, I get perfect picture till next power cycle, please help with ideas )

[Nicktronic]

Has anyone had success with this type of fix on the Q60T TVs that boot loop?

[smalt36]

Hi all,, having same issues on my UE50RU7100k except I dont get the booting sounds when unplugging the screen connectors, just a more stable backlight, is it possible to apply the same trick? board number is BN31 02703a. I also dont have the same ribbon connectors all of the tape fixes show, can the tape be applied to the main ribbon connectors from the board to screen boards?

EDIT!! Scrap that, ive just got it working perfectley with the tape method, the top ribbon connector, around 8 pins down and covered 4 roughly, dont really want to undo it to check but will if it helps anyone!

[ggil44]

Hi, I have a UN70NU6900FXZA and have read through the threads and tried the “fix” without any success. Same symptoms 2 blinks, unplug TV, disconnect ribbon cable, plug in TV and power up, wait for greeting tone then plug in ribbon cable and I get a perfect picture and sound. So, I de-soldered the 10-ohm resistor and replaced it with a 15K, then 35K, then 55K, then 98K, also tried connecting them to test point on the buffer board with a wire as shown in previous posts and nothing cured the problem. With those other resistors I can still do the start without ribbon cable and then plug in ribbon cable and get a normal picture. I don’t get a greeting tone with any of the other resistors replacing the 10-ohm resistor but I didn’t get one with the 10-ohm either. I have found that after a failed boot, I have to wait about 5 minutes for residual voltage to drain away before being able to get normal operation (Picture and sound) by plugging the TV in with a ribbon cable disconnected and then connecting the ribbon cable after the welcome sound otherwise it will go directly to the boot loop. At resistor 13246 when in normal operation I get 25.4V DC both sides.
I am not sure where to go from here, I guess I could keep adding higher value resistors but it doesn’t look promising. Any ideas? Is there a way the shorted components on the buffer board can be identified? Thanks,

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

Just want to add, the same model came in the shop today, i performed the same modification successfully.

The only difference, is i used a 30K resistor to replace the R13246 on the main board. I tried a 10K first and it was not successful. I also tried a 2K and it was not successful. I dont think exact resistance is crucial, but too low the tv will power cycle, too high you will see artifacts on the screen. Presumably from the VGH current being too limited.

No need to do the wire run thing if you can replace the SMD resistor without disturbing anything else on the board.

Model is UN70NU6900FXZA.

I wonder why this one needed 30k and the other one worked with 10k, same model.

[ChartronicsJenBoo]

Re: samsung un65nu6900f common problem, digging deeper

I can speculate that 10k is reducing inrush current. Otherwise the current spike is large enough and is detected as fault.
Did you measure VGH on other side of 10k resistor? Is it stable?
I think you can just install 10k in place of R13246 instead of running wire.

I removed a 10k resistor from another board and soldered it in place of R13246. The screen is on
when powered on and the continuous cycling has stopped. Also the picture seems to be normal as well.
Thank you all for this information, it was truly helpful and even more appreciated!

[RobertGHD]

Re: samsung un65nu6900f common problem, digging deeper

Hello.
I got a defective TV from a friend, a Samsung ue50tu8072 who seems to have the same problem but kind of different somehow. It still doesnt boot up and it is stuck in boot loop unless I disconnect the ribbon cable from the MB to the TCIO boards that control the display( or however are those long and narrow pcb attached to the display), or the short ribbon cable that connects the right TCIO to the LEFT one, left one being the culprit I assume. I managed to make it to boot if i cover pin 75 on the big ribbon cable between MB and TCIO but I get a very bad image (few green and grey lines all over the place and some white spots). Do you have any idea if there is any other fix I can try or at least what does the pin 75 exactly does? I also checked the VGH pin on the left TCIO and is reads around 8.5V if I remember correctly, but anyway is the same value as all chips on both TCIO. So VGH,VSS,CK1,CK2... etc. all read around 8.5V. Only the resistance is different between VGH and all other pins, VGH being around 80 Kohm and the rest around 1.2 Mohm. I dont remember the exact measurements beucase I didnt inted to post on forums in the first place, i thought it will be and easy tape fix as those youtube tutorials. Shame on me.

[jrcmann]

Re: samsung un65nu6900f common problem, digging deeper

Done. thanks

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Since i wont have it to test on the tv i can probably put on variable resistor that you can turn with a small screwdriver to set the appropriate resistance.

[jrcmann]

Re: samsung un65nu6900f common problem, digging deeper

I can't pm. I think im too new...

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

I'm having the exact same issue. Tape on pin 84 will get it to boot. But on reboot, I have to unplug the ribbon cable, till I hear the tone, then plug it in and bingo back up and running. Any idea where I can get this solder job done? I don't have the equipment anymore...

If you want to mail it to PA, my shop can do it. PM if interested and we will coordinate.

[jrcmann]

Re: samsung un65nu6900f common problem, digging deeper

I'm having the exact same issue. Tape on pin 84 will get it to boot. But on reboot, I have to unplug the ribbon cable, till I hear the tone, then plug it in and bingo back up and running. Any idea where I can get this solder job done? I don't have the equipment anymore...

[joelshort987654321]

Re: samsung un65nu6900f common problem, digging deeper

still working in 2023
thank you for the info

[joelshort987654321]

Re: samsung un65nu6900f common problem, digging deeper

Still working in 2023. Thank you so much

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

Cool, with that fix and the backlights run very low, at least people can get more use out of these crap tvs, before they buy a different brand next time.

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Just want to add, the same model came in the shop today, i performed the same modification successfully.

The only difference, is i used a 30K resistor to replace the R13246 on the main board. I tried a 10K first and it was not successful. I also tried a 2K and it was not successful. I dont think exact resistance is crucial, but too low the tv will power cycle, too high you will see artifacts on the screen. Presumably from the VGH current being too limited.

No need to do the wire run thing if you can replace the SMD resistor without disturbing anything else on the board.

Model is UN70NU6900FXZA.

[jtel electronics]

Re: samsung un65nu6900f common problem, digging deeper

Hi All, can anyone confirm the same pin number for the 50/55" versions

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Good to hear it working. As far as i am aware the original TV in thread is still working fine.

[codycowgill]

Re: samsung un65nu6900f common problem, digging deeper

Just repaired my un70nu6900f with this same method. Thank you!

Still going strong, probably used the tv for 20 or more hours. I forgot to mention that I used a 19k resistor.