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Shahid
Shahid, Technician
Category: TV
Satisfied Customers: 9829
Experience:  I have been repairing electronic gear since 1993 as a qualified Sony tech
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Samsung UN55D7000LFXZA Manufacture date: October 2011 Two

Customer Question

Samsung UN55D7000LFXZA
Manufacture date: October 2011
Two days ago the top 1/4 of the screen's LED's stopped working (I assume). The screen still shows a perfect image but it's noticeably darker (perfectly uniform line from the left to the right side) than the rest of the TV. The LED's have turned back on about 6 times (usually when the TV first starts) since this problem first started but they do not stay on for very long.
At this same time that the LED's went out, the TV began restarting on it's own occasionally. The screen goes black then the start up screen comes up (Samsung's Smart TV logo), the red power light flashes and you can hear the relay's clicking. However the two other Samsung devices I have hooked up to it (sound bar and Blu-Ray player) are set up to turn off when the TV does, but they don't turn off when the TV does this "reset". They do still turn off when I use the power button to turn off the TV.
Now the TV has started resetting its self more often, in fact it does it anytime I try to do anything online (Netflix, YouTube, etc.), open the "smart Hub", or make a change in the advanced picture settings. I'm currently watching TV (through an antenna) and listening to a sound bar through the ARC, and have been for a few hours without it restarting once.
I've tried "fixing" it by using it without any inputs connected, I've also unplugged the power cable to let the TV discharge and reset. I've also updated it to the most current firmware (1030) (as advised by Samsung support) through USB because the TV told me it's current firmware (1019) was "up to date" when I tried to do an online update through the TV settings.
I've also taken the back cover off to inspect for blown or bulging capacitors or bad solders, but saw nothing out of the ordinary.
I personally think it's the main board that needs replacing but unsure how to test it.
Submitted: 1 year ago.
Category: TV
Expert:  Shahid replied 1 year ago.

Hello, I'm Shahid and will be happy to assist you. I need additional info to troubleshoot the issue.

- Does the screen still show darker image on top 1/4 area?

- Does TV still turns Off and back On itself?

Thanks.

Customer: replied 1 year ago.
I've been watching TV for a few hours without restarting once. But the second I try to open "Smart Hub" it restarts. The same goes if I try to change certain picture settings or do anything in the Settings Menu that requires an internet connection.
Expert:  Shahid replied 1 year ago.

Thanks for the info. These symptoms indicate failing main board and only test is to check standby 5V DC supply from power supply board to main board with multimeter, if volts stay constant while TV resets then main board replacement is next step to resolve the problem.

Regarding darker image on top 1/4 portion of screen is an indication of failing LCD panel sorry about this news, entire LCD panel will be replaced to resolve the issue and this kind of repair may cost approx new TV price of same size so you would be better off with a new TV instead of spending money on screen replacement.

I wish I had better news about TV problems, I trust my input will help you out. Please feel free to respond if you have any additional questions.
A positive rating to answer would be greatly appreciated, please click on 5 star on this page then click submit/finish button so I can get credit on website for my work.
Regards,
Shahid.

Customer: replied 1 year ago.
I will test that, thank you.What about the output to the screen, does the board supply power to individual strips of LED's or are they wired in parallel so that if one has power they should all have power?Do you think the resetting problem and the dark area on the screen happening at the same time is tied to one faulty board or just horrible coincidence?
Expert:  Shahid replied 1 year ago.

I would say it is horrible coincidence that both problem occurred at same time, however, re-plugging LVDS cable between main board and t-con board (mounted under shield at bottom center of rear of screen) might help to get better picture on screen, darker image on specific section of screen isn't due to failing backlight LEDs in that area, in fact it indicates failing circuitry of LCD panel that process the video data coming from t-con board.

I hope these info will help, Please feel free to respond if you have any additional questions.
A positive rating to answer would be greatly appreciated, please click on 5 star on this page then click submit/finish button so I can get credit on website for my work.

Thanks.

Customer: replied 1 year ago.
Does power to the screen come from the power board and the picture from t-con?
Expert:  Shahid replied 1 year ago.

Let me explain it, power board sends volts to LEDs inside panel to produce backlight, main board controls all the functions of TV including backlight on-off and also process audio video signals, video signal data goes to t-con board that further process it and sends to internal circuitry of panel. LCD panel is a package of LCD screen for image/ picture and backlight system to glow the screen so we can view that picture.

Thanks.