Samsung LE40A856 vertical (image relative) color lines issue

[nafan]

Hello,

First of all : My english is not as good as I would like, so... Moderators, feel free to edit title in order to make it more relevant and more easy to find using search function.

As you can see on pictures, vertical moving lines are displayed since last week-end on our Samsung TV set, under and above white/bright areas (on every source : HDMI1-4, internal Tuner, etc...)

It never had a problem before, and it occured suddenly, with no physical shock, no electric shock (plugged on UPS), no excessive heat (it's winter, room temp is about 20°C).

I had no luck googling for this particular issue, but found a workaround on Youtube.
A guy named HammerToof "kind of" fixed it by entering Service Menu and lowering Sub-contrast setting.
I did it, and made the lines disappear at about 50 (the factory setting was 140).

But now, I'm looking for a serious fix...

So, I took off the back panel, cleaned dust, checked all connections (even if I don't think it's tab relative because lines are "following" bright pixels) without any result.

This TV set consumes 240Wh and produces moderate heat.
Considering that fans were full of dust, is there any chance a chip has a faulty solder and would need a reflow ?


If I correctly understand how all that stuff works, a T-con board problem would affect the whole screen.
As my issue is "image related" (lines follow bright areas), I should have a look at LVDS ?


I will attach pictures of backside tonight, light was awful yesterday evening when I disassembled the back cover.

[sordids999]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Hi,

I will as soon as I'll be back home (I'm at work for now).
I couldn't make a decent picture yesterday evening because there wasn't enough light.

Thanks for your interest.

[tom66]

Re: Samsung LE40A856 vertical (image relative) color lines issue

I believe this to be a panel fault, but I've never figured out the cause. I have an LE40A656 with nearly the same symptoms in the corner of my room for too long.

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Thank you for your reply, tom66.

Bad luck if it's a panel fault !

Did you try the "sub-contrast" trick on yours ?

[tom66]

Re: Samsung LE40A856 vertical (image relative) color lines issue

I found lowering user menu contrast to fix mine, except on user menus. But, not a permanent fix, still "in the pile" so to speak, will probably strip it down for bits soon.

[nomoresonys]

Re: Samsung LE40A856 vertical (image relative) color lines issue

maybe flex the panel see if display changes at all.

[tom66]

Re: Samsung LE40A856 vertical (image relative) color lines issue

maybe flex the panel see if display changes at all.

No change on mine.
It's strange, my parents reported same fault (suddenly there were lines) - I fixed the TV with bad caps, and gave it to them. Worked for 2 years then the panel goes, typical Samsung. (About 6 years old total.)

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Good morning,

I tried to flex the panel, but it would need a full disassembly of metal frame to do it right...

Here are some pictures of back side.

I checked temperature on boards with an infrared thermometer.
Almost everything is between 22°C and 30°C after half an hour, except a DIP16 and a transistor on Power Supply board (in the red rectangles) who reach quickly 40°C but don't get hotter.

There is also a noisy stuff in the big red rectangle on Power Supply picture.
I can't say if it's the black relay, one of the coils, or one of the white blocks, but it produces a low frequency electrical noise permanently (even if TV is switched off).

I'm afraid this won't help, but that is all I can share for the moment...

Thank you for reading.

[nafan]

Re: Samsung LE40A856 vertical color lines issue | New symptom at startup !

Hi,

New symptom since this week-end : a strange screen at startup.
And after a few seconds (heating ?) of this "8 bits barcode" artwork, the picture is correctly displayed.

It seems to me that a component is going to die...

Does this new symptom helps in my issue's diagnosis ?


Also, I have to correct myself about temperatures : some pieces of electronics run quite hot (60°C) when displaying dynamic/moving pictures for one hour or more.
These parts set on the long board in the left part : I think it's backlight related.


Thanks

[tom66]

Re: Samsung LE40A856 vertical (image relative) color lines issue

That looks even more like a bad panel, unfortunately! Mine isn't doing that yet though.

[Dang]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Been there a few times with very similar, if not the same issues, definitely with Tom66 on a bad panel so time to part it out I think.

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Ok, thank you for your quick answers.

I think it's time to find a replacement TV : the UE48H6400 seems to be a great Q/P ratio to me (can be found at 499€ in France), even if I don't really trust in Samsung any more...

And for my 6 years old LE40A856, do you think that someone may still be interested in parts (T-con, PSU, etc...) ?

[Dang]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Definitely, probably take a while considering it's semi-high end status but they will sell, T-con, main board, PSU and stand all worth around £30 each I would think.

[tom66]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Avoid buying a new Samsung TV. They are not well built and panels frequently fail like on this model, even for the newer models. Samsung are definitely the most troublesome of all the brands for panel faults.

My recommendations for LED-backlit LCD:
1. Panasonic
2. LG
3. Sharp/Toshiba BUT only if not rebadged (generally have to go >50" to avoid rebadged models)

or used/ex-stock Panasonic ST/VT/ZT60 plasma (or UT50/ST50) for best PQ, or Samsung F8500 plasma or used Pioneer Kuro 9G plasma. If your room lighting is well controlled (e.g. you can close curtains, screen reflections can be an issue), you will not regret buying a good plasma!

Probably better to get a good 1080p set rather than a mediocre 4k set, from what I've seen and heard at least from the low end 4k sets the picture quality (image accuracy) is very poor, much worse contrast ratio than 1080p set and also lower brightness. Generally makes the image seem washed out on anything not super bright/colourful.

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

Thanks,

I will probably buy a LED TV, because my children often watch movies in the afternoon, and our living room is very bright (lots of windows and lot of sun in south of France).

I don't want a 4K TV, and 3D is not needed (even if often included)

As I don't see lot of Panasonic on french websites, I will have a look at LG !

[nafan]

Re: Samsung LE40A856 vertical (image relative) color lines issue

I found a "PANASONIC TX-48AS640E Smart TV Full HD 3D 121 cm" for 500€.
Its price is nice, and the reviews are pretty good.

I'm now trying to understand Panasonic whole range of Led TVs.