samsung un65nu6900f common problem, digging deeper

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

Great tip Tech9pc, looks like samsung is going down in flames.

[tech9pc]

Re: samsung un65nu6900f common problem, digging deeper

Personally I would steer clear of the Samsung UN series and make sure you test with firestick or android box etc. Had a Samsung 58 inch mainboard fry my MSI RX 580 Gaming X 8GB video card plugged into HDMI port last year. Lost 400.00 video card for garbage samsung tv. Plus many complaints UN series blowing leds and causing tv to catch on fire and burn down their homes etc. I have plugged my PC into Skyworth, LG, RCA, SEIKI etc never a problem. learned my lesson lol.

[Davi.p]

Re: samsung un65nu6900f common problem, digging deeper

The higher R limits inrush and prevents ESD diode connected to VGH near Test point to go short, it is partially shorted.. my bet...

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

interesting thread, wonder why it worked for one and not the other, same model tv.

[codycowgill]

Re: samsung un65nu6900f common problem, digging deeper

Gotta be a design flaw of some sort. From what ive seen many of these TVs have this same problem (if that backlight leds dont burn up first anyway). Ive seen many people do the tape fix, which covers the bad VGH line, so if anyone out there with a tape fix wants to remove the tape and put a 10K resistor on the board to see.

I would like to see another get successfully repaired so we can rule out a fluke.

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

[ljmagyar]

Re: samsung un65nu6900f common problem, digging deeper

the direct resistor fix did not work.

nor did the wire to the Vgh port on the driver board with a resistor

[ljmagyar]

Re: samsung un65nu6900f common problem, digging deeper

I was gifted a non-working UN70NU6900F - same symptoms. I've determined that it is the right side of the driver board set (4 pieces) when viewed from the back. I can disconnect the flat cable between the two boards and start the TV with sound, and more often than not when I reconnect the flat cable (power ON) the picture comes on and TV works great until I shut it off.

I will try this fix (just replace the resistor) tonight and reply back.

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

yep, they're total junk and a fire hazard, absolutely the worse pos tv I've seen in forever.

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Not to be bearer of bad news. But these TVs were doomed from the start. “Nu” series have backlight issues where they get to hot, fail and melt the plastics beneath the screen. Glad you found a solution for your problem though. Great job troubleshooting

Oh totally. I have a decent sized pile of them at my shop with burn marks all over the diffuser, some cracked, some melted through the back white sheet.
What an absolute mess of a tv design.

I was actually rather sure when i saw the model number this was going to be a burnt up backlight as well. After the fix/mod i turned the backlight very low and advised the owner to keep it there. I usually advise "Keep the backlight as low as you can tolerate". If they ask why, i have a NU series diffuser to display and that gets the point across pretty quickly ha

[Storyteller12]

Re: samsung un65nu6900f common problem, digging deeper

Not to be bearer of bad news. But these TVs were doomed from the start. “Nu” series have backlight issues where they get to hot, fail and melt the plastics beneath the screen. Glad you found a solution for your problem though. Great job troubleshooting

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

Gotta be a design flaw of some sort. From what ive seen many of these TVs have this same problem (if that backlight leds dont burn up first anyway). Ive seen many people do the tape fix, which covers the bad VGH line, so if anyone out there with a tape fix wants to remove the tape and put a 10K resistor on the board to see.

I would like to see another get successfully repaired so we can rule out a fluke.

yes, I would like to see if this works in lieu of the tape cut-off method also.

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

i wish yours found will be the answer.. to tell the truth i checked on MB TU the back side of the boards are complete different circuit. so my questions did you follow the pins 85 from downside too?

I apologize, but i do not understand what you are asking. I believe the backside of this circuit board is completely flat with only the green coating on it.

[Diah]

Re: samsung un65nu6900f common problem, digging deeper

i wish yours found will be the answer.. to tell the truth i checked on MB TU the back side of the boards are complete different circuit. so my questions did you follow the pins 85 from downside too?

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Gotta be a design flaw of some sort. From what ive seen many of these TVs have this same problem (if that backlight leds dont burn up first anyway). Ive seen many people do the tape fix, which covers the bad VGH line, so if anyone out there with a tape fix wants to remove the tape and put a 10K resistor on the board to see.

I would like to see another get successfully repaired so we can rule out a fluke.

[nomoresonys]

Re: samsung un65nu6900f common problem, digging deeper

so you think this is a design flaw then? or maybe more planned obsolescence they are putting in, since the overdriven backlights etc. has been figured out. maybe they are trying to be more subtle where they put the weak link?

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

Just to clear this up, it is in fact pin 84. It is hard to tell from my photo because of my black marker, but that trace does wrap around and go up to the resistor.

The pin name should be VGHD_30V_PW, but is shown as a NC in the manual. I can confirm that on both the old board and the new board a 10ohm resistor is present in the R13246 position.

[itelite]

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.

Yes all seems stable. Yes i thought of that after it was all back together. 10k in place of the 10 ohm PCB resistor should effectively accomplish the same thing. Im sure i will see another one with this problem soon enough to give it a try.

[alfatv]

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.

[Diah]

Re: samsung un65nu6900f common problem, digging deeper

I believe it is listed as VGH30V or something similar (pin 84). It is actually listed as a NC in the 65" service manual. I do not have the manual for the 70.

It appears to be another version of pin 11 on the other LVDS connector. I would imagine that would be another place to look if this location in the circuit measures correctly.

its as i mensioned before Pin 75 STVP_MB4
all TU /NU/MU size share same sockets design & MB

[itelite]

Re: samsung un65nu6900f common problem, digging deeper

I believe it is listed as VGH30V or something similar (pin 84). It is actually listed as a NC in the 65" service manual. I do not have the manual for the 70.

It appears to be another version of pin 11 on the other LVDS connector. I would imagine that would be another place to look if this location in the circuit measures correctly.