samsung un65nu6900f common problem, digging deeper

[joelshort987654321]

Re: samsung un65nu6900f common problem, digging deeper

Still working in 2023. Thank you so much

[joelshort987654321]

Re: samsung un65nu6900f common problem, digging deeper

still working in 2023
thank you for the info

[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...

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

[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

Done. thanks

[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.

[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!

[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.

[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,

[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!

[Nicktronic]

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

[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 )

[ggil44]

Hello xfox, I have the same problem with the same TV (UN70NU6900FXZA). I found that if I tape pins 13 - 24 on the Right ribbon cable (shorter one) that I can eliminate the boot loop but I get the dreaded color fade from left to right with the picture otherwise, the TV works normally.

[nomoresonys]

Try the tape method.

[xfox]

Just tried, was not able to get a picture but if I cover one of pins, TV is not restarting so if you look at main board top ribbon (right on LCD) second or one before last, and on lower ribbon (left on LCD) first and last, covering any of those pins will get tv of power cycling but there is no picture.

[nomoresonys]

Interesting, my memory is bad, hopefully a member who has been diving deep on these address boards and pin masking can help, sometimes the short can not be "fixed" with taping.

[xfox]

Btw, I have no ground on pin 2

[EazyBone]

I just got one of these 65 inch that is, the main board is slightly different as those resistors arent present, anyone found a fix for the actual model in the post? Same reboot. Thx

[xfox]

Tried everything... And I got one idea... what if I'll put some delay switch like this https://www.aliexpress.us/item/32568...100001074166_4

[itelite]

My feeling is that you must be doing the mod incorrectly. Everything you are describing suggests that you are having the same problem with the same equipment. Post some high quality pictures of your work. See if we can sort out where it's going wrong. Ive done quite a few of these, and this always works with various resistance values.

Something I've found to be helpful is to use a potentiometer in place of the resistor, that way you can adjust the resistance to see where it boots properly and where is doesn't. Note the results, and you have your tolerance window.

Maybe yours has a smaller tolerance window, but that would be my last place to look.

Beyond that, if you want to try your delay thing, simulate it first with a wire. Connect a wire to the correct points, snip the wire in half and strip the insulation. Turn tv on, count to 5, put the wire back together. Observe results.