Samsung UN75MU8000 With some picture dark spots

[jason123]

First thought is bad LED section. However this looks more like burn, either panel or underneath? Not sure what to make of it. Any thoughts?? This is a massive 75" TV, and I'd rather not open it up if it's a panel issue as chances of getting it running 100% after that are.. well as you know

[alfatv]

Re: Samsung UN75MU8000 With some picture dark spots

Is this your TV or did you get it from someone? Maybe not LED, but it does look like backlight problem.

[dick_barton]

Re: Samsung UN75MU8000 With some picture dark spots

I wonder if the leds have been melting the edge of the polarising sheet as been discussed and pictured several time on the Forum.

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

Is this your TV or did you get it from someone? Maybe not LED, but it does look like backlight problem.

Hi
Just bought it from someone. It's a nice 75" TV, and I couldn't pass $30 for it.. The external One Connect is more than $50

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

I wonder if the leds have been melting the edge of the polarising sheet as been discussed and pictured several time on the Forum.

I have seen that on Samsung MU series, so it's likely.. but I've never seen the effect looking like this.

[DXseekerMO]

Re: Samsung UN75MU8000 With some picture dark spots

I have seen that on Samsung MU series, so it's likely.. but I've never seen the effect looking like this.

Are there any dark spots or uneven light distribution upon the bottom of the screen? Please take a picture of the whole screen while the TV is on and post it here.

If you ask me, it looks like a moth or debris somehow got in between the diffusion layers behind the screen right behind that spot.

[Storyteller12]

Re: Samsung UN75MU8000 With some picture dark spots

I’ve seen this before. Not sure it’s the same problem, but looks like it. Someone tried replacing leds on a tv I got before. But when putting it Back together they didn’t seat the white sheet with holes in it that goes over the leds. Sorry not sure the technical term for that sheet. Anyways it fell out of place and looked just like that.

If it’s not that most likely backlights. Unfortunately looks like you will need to disassemble the whole tv either way to find out. Good luck keep us posted on the outcome

[DXseekerMO]

Re: Samsung UN75MU8000 With some picture dark spots

I've seen this before. Not sure it's the same problem, but looks like it. Someone tried replacing leds on a tv I got before. But when putting it Back together they didn't seat the white sheet with holes in it that goes over the leds. Sorry not sure the technical term for that sheet. Anyways it fell out of place and looked just like that.

If it's not that most likely backlights. Unfortunately looks like you will need to disassemble the whole tv either way to find out. Good luck keep us posted on the outcome

The white sheet is called a reflector sheet. This is an edge-lit TV so on this model seating the reflector sheet around the LEDs doesn't apply. The LEDs are at the bottom of the TV and shine up in to a thick plastic diffuser. The reflector sheet is behind this "main diffuser" and has no LED cut-outs in it.

[Storyteller12]

Re: Samsung UN75MU8000 With some picture dark spots

The white sheet is called a reflector sheet. This is an edge-lit TV so on this model seating the reflector sheet around the LEDs doesn't apply. The LEDs are at the bottom of the TV and shine up in to a thick plastic diffuser. The reflector sheet is behind this "main diffuser" and has no LED cut-outs in it.

Thanks for the info. I've worked on a few lower end models of the mu series and they were backlit. Didn't know this model was edgelit.

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

Are there any dark spots or uneven light distribution upon the bottom of the screen? Please take a picture of the whole screen while the TV is on and post it here.

If you ask me, it looks like a moth or debris somehow got in between the diffusion layers behind the screen right behind that spot.

Hope this helps.. I don't really know what to think. I don't believe backlight related based on photos I'm sharing. I could be wrong

[budwich]

Re: Samsung UN75MU8000 With some picture dark spots

third picture shows a problem with a vertical driver in the top left corner. This is likely impacting "drives" along the panel related to overall voltages therein. You might get lucky and find a "less than working" smd capacitor in the bottom driver boards. This type of problem (ie. capacitors on the driver boards) is somewhat common across sets, usually, with complete shorts or otherwise. You can perhaps isolate things by doing some "disconnect tcon to panel" tests to determine a bit more. Go from the result. Of course, take care working with such a large panel... but it can be readily done.

Having said that, there is also the possibility of "window washing"... if you get to the bottom frame of the panel, is there any signs of "contamination" that has occurred.

[mmartell]

Re: Samsung UN75MU8000 With some picture dark spots

That may be a reflection, doesn't seem parallel to the side ?

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

third picture shows a problem with a vertical driver in the top left corner. This is likely impacting "drives" along the panel related to overall voltages therein. You might get lucky and find a "less than working" smd capacitor in the bottom driver boards. This type of problem (ie. capacitors on the driver boards) is somewhat common across sets, usually, with complete shorts or otherwise. You can perhaps isolate things by doing some "disconnect tcon to panel" tests to determine a bit more. Go from the result. Of course, take care working with such a large panel... but it can be readily done.

Having said that, there is also the possibility of "window washing"... if you get to the bottom frame of the panel, is there any signs of "contamination" that has occurred.

If you're referring to far left corner, upper vertical bright line, it is a reflection off the window blinds gap.. Sorry

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

That may be a reflection, doesn't seem parallel to the side ?

You are correct.. reflection

[DXseekerMO]

Re: Samsung UN75MU8000 With some picture dark spots

That is definitely not something in between the layers of diffusion. In one of the earlier pictures it looked like one spot, but with that tracer going from that spot to the right side on these new pictures it looks like a screen issue, like stuck pixels or something. If there's no contamination at the bottom of the panel as budwich suggested I'd bet the screen itself is bad.

I wonder if some kid touched the panel not so hard to crack it, but hard enough to maybe affect the picture?

Has anyone ever seen anything like this? I haven't.

Following

[jason123]

Re: Samsung UN75MU8000 With some picture dark spots

Ok, I was hoping to find some burns or dirt or something inside.. it was absolutely clean, with LEDs all on, and no issues. Turns out to be somehow a panel problem

[RDC55]

Re: Samsung UN75MU8000 With some picture dark spots

Has anyone ever seen anything like this? I haven't.:

Samsung UN60D6000SF Manufactured 2012

Not exactly the same but similar? I have yet to tear this one down to look at the light guide / diffuser sheets.

In the thread I started it was suggested that it may be caused by a scratch on the light guide. It was one of those where you get it with no video, proudly repair it only to have a no joy feeling when you see a screen defect :-(

https://www.badcaps.net/forum/showth...35#post1011635

[neilc6]

Re: Samsung UN75MU8000 With some picture dark spots

I think all the D model years were edge lit LED. If it's green, then it's likely a panel issue.