Hi, I have a Samsung UE46D5520 TV with a backlight problem, for which I need some advice. It uses edge-mounted LEDs for the backlight, along the top of the screen only.
The first two attached pics demonstrate the symptoms before opening up the TV. The first pic is a testcard, the second is a pure white still picture. Note that the horizontal lines on the white picture are an artifact of the camera and aren't there in real life.
You'll see that the left-most roughly quarter of the top of the display is in shadow. The next quarter looks like it is too bright. The right half is fine.
The third pic is after removing the bezel, and with the set upside down, so you can see the backlight leaking out. The fourth pic is supposed to show that the top-left quarter of the LEDs are completely unlit.
I see that the backlight strip is actually made of two strips, a left and a right, each of which has 72 LEDs (144 LEDs in total). The left-most 36 of the LEDs in the left strip don't seem to light at all.
The numbers intrigue me, as 36 is obviously exactly half of 72. Is that just a coincidence? I understand that the LEDs are wired in series, so if one fails, all the others after that will not light, so I guess the first one that isn't lit after the lit ones is dead. Is that right?
The fifth pic shows the LED strip after taken out of the TV. The connector on the left is in the top-left corner of the TV. The 36 leftmost LEDs do not light (the 36 LEDs closest to the connector). The sixth pic shows the LED that is the first one that doesn't light to the left of the 36 that do. It is marked with a pencil mark just under the LED. I can't see anything wrong with it with the naked eye but I guess that is the problem.
Interestingly, I notice that one LED (seventh pic) is completely missing close to the left edge (this isn't the case on the right strip). The panel doesn't look like it's ever been opened, and I can't see an LED rattling around loose inside, so my guess is that is how it has been since it was first assembled.
Is it easy to fix or replace individual LEDs? I guess I would need two. Any idea what ones to buy?
The first two attached pics demonstrate the symptoms before opening up the TV. The first pic is a testcard, the second is a pure white still picture. Note that the horizontal lines on the white picture are an artifact of the camera and aren't there in real life.
You'll see that the left-most roughly quarter of the top of the display is in shadow. The next quarter looks like it is too bright. The right half is fine.
The third pic is after removing the bezel, and with the set upside down, so you can see the backlight leaking out. The fourth pic is supposed to show that the top-left quarter of the LEDs are completely unlit.
I see that the backlight strip is actually made of two strips, a left and a right, each of which has 72 LEDs (144 LEDs in total). The left-most 36 of the LEDs in the left strip don't seem to light at all.
The numbers intrigue me, as 36 is obviously exactly half of 72. Is that just a coincidence? I understand that the LEDs are wired in series, so if one fails, all the others after that will not light, so I guess the first one that isn't lit after the lit ones is dead. Is that right?
The fifth pic shows the LED strip after taken out of the TV. The connector on the left is in the top-left corner of the TV. The 36 leftmost LEDs do not light (the 36 LEDs closest to the connector). The sixth pic shows the LED that is the first one that doesn't light to the left of the 36 that do. It is marked with a pencil mark just under the LED. I can't see anything wrong with it with the naked eye but I guess that is the problem.
Interestingly, I notice that one LED (seventh pic) is completely missing close to the left edge (this isn't the case on the right strip). The panel doesn't look like it's ever been opened, and I can't see an LED rattling around loose inside, so my guess is that is how it has been since it was first assembled.
Is it easy to fix or replace individual LEDs? I guess I would need two. Any idea what ones to buy?
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