47ln5400 dimming

[cmg3631]

Hey Guys!

I am having a problem with this 47ln5400. I replaced a bad LED strip and put everything back together. Turned it on and it works great except for the fact that the left side of the screen, about the last 1/4 of it, dims and brightens at 2 second intervals. It doesn't do it when I have it torn down to the LEDs. They stay on constant. However when I put the screen back on it does it again. Upgraded firmware, same problem. Although it is watchable and has a great picture, the dimming is very annoying to me

Any ideas would be greatly appreciated!

Chris

[diif]

Re: 47ln5400 dimming

Sounds like a faulty LED on the strip.

[cmg3631]

Re: 47ln5400 dimming

They are all working..That's what has me confused.

[diif]

Re: 47ln5400 dimming

How are the LEDs wired ? Photos help.
How did you test the LED strip before fitting ? Could be a faulty LED that passed with a low current LED tester but under full power is failing.

[cmg3631]

Re: 47ln5400 dimming

I tested the strip with a tester, but then fired the set up after installation and all are working fine. It's definitely a rythmic pulse, but only afteer I connect the screen.

[diif]

Re: 47ln5400 dimming

So if you disconnect the two ribbon cables from the tcon to the panel and power the TV on it lights it perfectly with no flickering ?

[cmg3631]

Re: 47ln5400 dimming

Yes, that would be the case.

[budm]

Re: 47ln5400 dimming

Can we see the pictures of the whole backside of the TV so we can see how all the boards are connected together?

[budm]

Re: 47ln5400 dimming

"Turned it on and it works great except for the fact that the left side of the screen, about the last 1/4 of it, dims and brightens at 2 second intervals."
The

[budm]

Re: 47ln5400 dimming

"Turned it on and it works great except for the fact that the left side of the screen, about the last 1/4 of it, dims and brightens at 2 second intervals."
It has two set of LED strings (3 strips (with 2-sub strips per strip) are connected in series to form one string) and two LED drivers, they are lit up full horizontally so I cannot see that you have problem with just one side of the screen since All the led in the string will light up or none at all if one LED is open, or if one shorted then you will see dark shadow on the screen.
The whole string has to be flickering not just part of the string, LCD panel cannot cause just some section of the LED to be flickering, think of it as two set of Christmas lights.
This picture show one string not working.
You have six LED strips, correct?
What happen if you turn down the backlights level?
Are you sure it is not the image that is flickering?

[cmg3631]

Re: 47ln5400 dimming

Hi Bud!

I am sure that all LEDs are working. If I can post a video on here I will, but I will explain as best I can. It doesn't flicker so much as it is normal for about 2-3 seconds then dims for 2-3 seconds. It doesn't lose the picture, but not as bright. I noticed last night when I paused it on a image that lights up the whole screen that it appears to be occurring in the upper left part of the screen. Adjusting back light, picture, and anything else I tried does not change this phenomena.