Samsung LED TV Backlight Problem

[venkygec]

I have a Samsung 46" 3D LED HDTV ( UA46ES6200M ) and is of warranty.

The problem is exactly top half of the Screen is dark. Bottom half is perfect.
I can see the picture on the Top Half, but it is very badly lit and is uniformly dark (i.e. it is not in patches).

This problem appeared few months back, but after 1 week everything was fine. Now it started again and its more than month and is not going.

When i called the service center engineer, they said the entire panel needs to be changed. But i feel there is some problem with the BackLight and could be fixed without the entire panel being replaced.

Could someone please advise, exactly what could be the problematic part and how it can be fixed?

Thanks

 

[Glenn_26]

I myself had the Samsung LED ultra thin which I bought it 3 years ago. Now it have 3 inches circle black spot in the middle of the screen. I called Samsung since it's out of warranty they don't cover anymore the parts and repair in it. Well, I had 3 Samsung older 1LED, and 2 LCD flatscreen tv at home don't have this problem. I don't think so that this expensive LED Ultra thin Samsung LED TV will last only for about 3 to 4 years and have problems. Please Samsung answer your bullshit cover the cost of a defective parts. From this time I don't have any plan to spend any money on Samsung product since it will not last long. Hope consumers will be aware of this since Samsung are not aware of their responsibility of such trash product..

 

[lostcaper61]

I had same problem tv would go off and on. Drove me nuts!
Brought tv to samsung recommended service center. They couldn't find anything wrong with tv. Told me to reboot my cable box (unplug for 10 minutes ) then plug everything back in. Never had a problem since. That was over a year ago. Good luck

 

[conundrum_7]

Just fixed mine, problem was two (!) open circuit diodes right in the middle of the screen.
In this case I swapped the middle two strips for outer ones, my first repair lasted 1.5 months but this time
the LEDs themselves have been replaced with identical (2.53 versus 2.42V) Al2O3 based emitters with enhanced 60/40 solder
in the hope that this does last.

I am in the process of adding monitoring to see if this repair will be reliable, in the process of documenting on Hackaday.
Seems that the problem is overheating and as a result a long term fix will need to address this.
I did notice that there is a "hot spot" in the approximate centre which seems to originate from the main IC that runs at around 42.3C with moderate use. If this is indeed the problem a simple heatsink would help as would a fan due to this chip heating up more when displaying active content.
Also failing LEDs apart from looking dimmer typically read 2-3C hotter than surrounding ones.

 

[lostcaper61]

I'm finished with samsung!
Just had my tv back to a service center... top 1/3 of tv was dark. .. rest of screen was fine. Two weeks later poof!! Black screen. Technician called and told me the power supply is the problem. Cost to fix... $650.00 + tax.
The tv is a 2013 model.I got 3 years out of a tv! Never ever another samsung product coming into this house.
Unfortunately, today we're in a throw away society.

 

[conundrum_7]

Hi, do you still have it? I would be interested to see if my spare tested backlight strips would work.
I also have a power board here and yes it is a simple fix (bad diode in PSU) which takes less than half an hour to do.
Can talk you through a repair, at this point my TV is usable but would prefer to tinker with it as also going to add additional failsafes and Neopixel/APA102C strips in addition to the old backlights so that it can be used for room lighting and switch between them using a simple series high side MOSFET, already added GITD security lighting strip for diagnostics purposes.
Turns out that with this one at least the LCD is quite translucent when unpowered.

To change the strips on these is feasible and mine took less than an hour to disassemble and get the (quite fragile) glass panel out.
Each strip is held in by little press connectors which you need a special tool for removal.
Interestingly the difference between different models is a shorter or longer RH strip so sometimes they can be interchanged in one direction only.
Diodes typically drop 2.42-2.51V on my meter (MM20P) but any which measure open between the two test pads on either side are bad.
Middle LED is not the same and could explain why these invariably fail so soon after manufacturer, it routes wiring differently to the others but is an identical part.